The cult of amphioxus in German Darwinism; or, Our gelatinous ancestors in Naples’ blue and balmy bay

Biologists having rediscovered amphioxus, also known as the lancelet or Branchiostoma, it is time to reassess its place in early Darwinist debates over vertebrate origins. While the advent of the ascidian–amphioxus theory and challenges from various competitors have been documented, this article offers a richer account of the public appeal of amphioxus as a primitive ancestor. The focus is on how the ‘German Darwin’ Ernst Haeckel persuaded general magazine and newspaper readers to revere this “flesh of our flesh and blood of our blood”, and especially on Das neue Laienbrevier des Haeckelismus (The new lay breviary of Haeckelism) by Moritz Reymond with cartoons by Fritz Steub. From the late 1870s these successful little books of verse introduced the Neapolitan discoveries that made the animal’s name and satirized Haeckel’s rise as high priest of its cult. One song is reproduced and translated here, with a contemporary “imitation” by the Canadian palaeontologist Edward John Chapman, and extracts from others. Predating the American “It’s a long way from amphioxus” by decades, these rhymes dramatize neglected ‘species politics’ of Darwinism and highlight the roles of humour in negotiating evolution.


Flesh of our flesh
In 1834 Costa, a professor of zoology embarking on a big study of the rich fauna of the Kingdom of Naples, reclassified what, from a preserved Cornish specimen, the German zoologist Peter Simon Pallas had 60 years before described and depicted as a mollusc. Costa placed live animals from Posillipo, just north of the city, as relatives of cyclostomes, the jawless hagfish and lampreys, though dissection soon showed that amphioxus deviated more from these than they did from salamanders (Willey 1894, pp. 7-9). Costa's interest in links between classes and Europe-wide discussion as an intermediate form (De Ceglie 1999, pp. 87-99) confirmed amphioxus as the most primitive vertebrate (Gegenbaur 1859, pp. 386-393). In the 1860s the Jena zoologist Ernst Haeckel, with his anatomist colleague Carl Gegenbaur, evolutionized the science of form (Nyhart 1995;Richards 2008;Hopwood 2015, pp. 61-88) and gave it an even bigger part.
Haeckel filled the first Darwinist system, his Generelle Morphologie (General morphology), with cosmic ambition, new technical terms, ferocious polemic, bold pedigrees all the way up to human beings and taxonomic revisions which promoted amphioxus to a new subphylum, the Acrania or skull-less ones. As the single survivor of the first vertebrate division, Haeckel pronounced it ''probably the last Mohican'' of a once ''richly developed and many-branched tree'' (Haeckel 1866, II, p. cxix). The reference to James Fenimore Cooper's novel invoked imperialist elegies for the last representatives of lineages, tribes and species (Stafford 1994, pp. 232-260;Brantlinger 2003), but Haeckel in fact picked winners, stressing the nobility of amphioxus as an ancestor of the dominant line and the respect owed to age. The transition from the invertebrates to amphioxus remained mysterious, however; he adopted a marine roundworm as a hypothetical link, but there was as yet no convincing bridge.
From 1868 Haeckel's Natürliche Schöpfungsgeschichte (Natural history of creation) preached this Darwinist gospel and, over several decades, a dozen German editions and as many translations took it to the general educated public. Lacking fossils, his conjectural pedigrees relied on embryos, via the theory that individual development (ontogeny) recapitulates that of the species (phylogeny). Still cautious about vertebrate origins in 1866, Haeckel now used Kowalevsky's work to argue that an invertebrate like an ascidian larva, itself derived from annelids, had developed in two directions: degenerating into the adult tunicates sitting on the sea floor and progressing to amphioxus and other vertebrates (Haeckel 1868a, pp. 409, 433-440). This story raised the credibility of the lancelet too. ''We must thus contemplate amphioxus with special reverence'', a ''popular scientific lecture'' proclaimed, ''as that venerable animal which of all still living animals is alone in a position to give us an approximate idea of our oldest Silurian ancestors with backbones'' (Haeckel 1868b, p. 42). Fine schematic plates of ascidians and amphioxus graced the second edition of the Schöpfungsgeschichte, bridging a ''deep gulf'' and allowing Haeckel to trace humans back to worms (Fig. 1). He told ''speculative philosophers'' to stop ''building futile castles in the air'' and think about these facts instead (Haeckel 1870, p. 673). Darwin's Descent of Man less polemically promoted the ascidian-amphioxus theory the following year (Darwin 1871, I, pp. 204-206). Humble origins were an old idea-liberals cared only how far a person had come and could go-but the specificity and degree of consensus were new.
Haeckel's pedigrees stirred up trouble from the start, but editors, journalists and general readers entrenched the Schöpfungsgeschichte in the optimistic, nationalist, anticlerical 'culture of progress' of the new German Empire and took these ancestors into middle-class homes. 4 Then, in 1874, Haeckel came out with the Anthropogenie (translated as The Evolution of Man), a major statement of the relations between ontogeny and phylogeny and a salvo in the Kulturkampf, Chancellor Bismarck's anti-Catholic campaign (Haeckel 1874, pp. xi-xvi). Joining the nationalist monument-building (Belgum 1998, pp. 84-102;Jefferies 2003, pp. 59-72), the book proudly traced humanity back to amoeba, amphioxus, axolotl, Australian lungfish and ape (Hopwood 2015, pp. 108-119). Haeckel told readers that ''ignorant theologians'' and ''anthropocentric'' philosophers objected that his attitude towards amphioxus had ''ridden roughshod over … the dignity of humanity and most grievously insulted the divine human sense of reason''. But, he insisted, the ''thousand-year-old oak wood'' it seemed natural to respect was as nothing compared to this little fish. If amphioxus lacked ''skull, brain and limbs'', this ''flesh of our flesh and blood of our blood'' still deserved more admiration and reverence ''than all the useless rabble of so-called saints to whom our 'highly civilized' nations build temples and dedicate processions'' (Haeckel 1874, pp. 337, 340). Haeckel deployed fresh empirical research and his own new argument that all true animals descended from a swimming stomach, or gastraea, to strengthen and expand his coverage of the ascidian-amphioxus theory (Beeson 1978, pp. 335-356). He mobilized these animals as secular icons and in a struggle for embryology between phylogeny and physiology that politicized species choice (Hopwood 2011, p. 5). One look at amphioxus development, he declared, and the chick-based theory of his rival, Wilhelm His, ''collapses like a house of cards'' (Haeckel 1874, p. 629;also 1875, p. 23).
More specialized than the Schöpfungsgeschichte, and hard for those Haeckel disparaged as ''so-called educated'' graduates of the classical grammar schools (Haeckel 1874, p. xi), the Anthropogenie disappointed high expectations of a good read, but many learned the arguments at second hand (Hopwood 2015, pp. 127-134). The liberal publicity machine announced the book with a review in the Illustrirte Zeitung (Illustrated news) that told progressives to study comparative embryology. Large wood engravings presented amphioxus and ascidians as ''primordial ancestors of the tribe of backboned animals'' (Fig. 2). 5 Die Gartenlaube (The bower), the family magazine with the huge run of nearly 400,000, also stressed their significance as a bridge. Without the ''little lancet fish'' we would   Haeckel's Anthropogenie are cruder than the original plates but reached more people. The magazine omitted cross-sections and a lamprey larva that Haeckel had added to present his more developed theory in the more specialized book. Zacharias (1875a, p. 68). 41 9 29 cm. Niedersächsische Staats-und Universitätsbibliothek Göttingen barely know we came from worms, a ''kinship certainly more congenial to the Christian feeling of humility than descent from the apes''. 6 But the Anthropogenie did not just give journalists material; it also goaded experts into warning the public (Hopwood 2015, pp. 119-126, 132-134).
Haeckel basked in adulation, but his polarizing rhetoric also provoked howls of opposition from scientists as well as philosophers and theologians. A disciplinary enemy, the physiologist Emil du Bois-Reymond, had already attacked his overstepping of the bounds of natural knowledge (Bayertz et al. 2007). Even fellow zoologists, most of whom by now accepted the fact of evolution, worried about the dogmatic presentation of personal speculations, exaggeration of his own novelty and intolerance towards other researchers' views. Few Darwinists endorsed every detail of his pedigrees and many objected to his gastraea theory (Nyhart 1995, pp. 168-206). Yet amphioxus had until now largely escaped specialist challenge.
Haeckel's advocacy and Darwin's endorsement had established the lancelet as the primordial vertebrate and built momentum behind the more controversial ascidian theory, but from 1875 other Darwinist theories began to compete (Beeson 1978). 7 From Naples, Anton Dohrn urged followers of Haeckel and Gegenbaur to pay living conditions more attention. Then they would see that ascidians and amphioxus merely continued the degeneration that the parasitic cyclostomes had begun. Reduced to filtering food from sandy water, amphioxus represented ''a degenerate fish'', and the ascidians had declined even more (Dohrn 1875, p. 55;Ghiselin 1994, p. 63). For the Würzburg zoologist and authority on sea cucumbers Carl Semper, the other main advocate of the annelid theory, amphioxus was also no vertebrate (Semper 1875, p. 66;1876a). This comment in Semper's institute journal gained currency when the veteran materialist and early Darwinist Carl Vogt deployed it in the liberal Frankfurter Zeitung to dismiss Haeckel's ''mythical'' pedigrees, and anti-Darwinists picked it up. 8 Few were in any position to adjudicate, but expert disagreement made the choices look arbitrary and helped those who rejected pedigrees out of hand.
Haeckel defended himself, in a small section of a long polemic, by pretending that for consistency Dohrn would have to make the whole animal kingdom degenerate from the ''sinless'' Adam until the ''unfortunate amphioxus, which had burdened itself with the most serious guilt, finally lost even its head'' (Haeckel 1875, pp. 31-33, 88-89). But as religious and political protests rained down on Haeckel, and the press amplified colleagues' censure of everything from pictures of embryos to speculations about cellular souls, objections to amphioxus as ancestor were still easily overlooked. For spokesmen of science the bigger issue was the threat from his behaviour to their freedom in the new state. In early 1876 Semper publicly targeted Haeckelism for falling into the same credulous dogmatism that its author repudiated in the churches, and so risking the status that Darwinism had brought zoology, but he mentioned amphioxus only in a note (Semper 1876b, p. 35).
Haeckel's reputation would never recover fully from these battles, but most competent researchers still credited him for pushing the theory of evolution through. As tempers frayed, humour, which had so far figured mostly in sarcasm between Haeckel and his critics, appeared as mediator. Rhymes went some way towards defusing a tense situation by separating Haeckel's excesses from commitments on which evolutionists just might agree.

Haeckelism in rhymes
Nature researchers in the German lands had long sung together to foster (male) camaraderie and cultural nationalism, validate specialized knowledge (Jackson 2003), and share the fun in songs such as Joseph Victor Scheffel's mock-tragic lament by the last ichthyosaur. A commission from the Bern scientific society spurred the newspaper editor Moritz Reymond to write humorous verses on intellectual fashions such as the Kulturkampf and medical advice, and Haeckelism became his greatest theme. 9 With a title referring to Catholic books of daily prayers and the like for non-priests, and a focus on the Old Testament, Das neue Laienbrevier des Haeckelismus (The new lay breviary of Haeckelism) eventually ran to five books with cartoons by Fritz Steub of the Fliegende Blätter, the Bavarian Punch.
Reymond prepared Genesis, oder die Entwickelung des Menschengeschlechts (Genesis, or the development of the human race) for Christmas 1876. Shrinking the octavo lectures of the Anthropogenie chapter by chapter to a sexto-decimo of songs painlessly acquainted readers with the positive and negative sides of the original. Engaging with its reception too, the satire played on the symmetry between Haeckel's charges of ignorance and the exclusivity of his own neologisms, on the one hand, and the irony of his condemning church dogma while setting himself up as the ''apostle of a new faith'', on the other (Reymond 1877, p. 8). Reymond tackled the pedigrees at length, but left the hypothesis of amphioxus as ancestor unchallenged; the consensus was too strong and dissent not yet prominent enough. Two songs reviewed the discoveries that had revealed respectively the structure of amphioxus and ascidians and their embryology and thematized the German tradition of finding origins in and around the Mediterranean.
The first, to a folk tune previously used for a student song about Diogenes the Cynic and Alexander the Great, corresponded to Chapter 13 of the Anthropogenie and tells how zoologists' lancets raised the status of the lancelet (Reymond 1877, pp. 76-79). A series of encounters with Costa, Kowalevsky and Haeckel, the extent of whose hands-on research is exaggerated, prove fatal for the individual animals. Invoking Pallas fails to stop Costa testing his hunch (Fig. 3). But the species gain fame. Here is the complete song, ''Der Körperbau des Amphioxus und der Ascidie'' (The structure of amphioxus and ascidian), with my translation but without the four endnotes that explained the history in quotations from the Anthropogenie.

Ein schlüpfriges Lanzettenthier
A lancet fish so slippery Lag wohlgemuth im Sande Lay cheerfully in the sand Und dachte: ''Ei wie schön ist's hier And thought, ''Oh, isn't it lovely An Posilippo's 10 Strande!'' Here on Posillipo's strand!''  Fig. 4, was added in the second and kept in this third edition. Reymond (1878, p. 108 The stem of our ancestral stocks Bring Jeder seine ''Blume''! Let everyone toast your name! Listeners were invited to drink to their newest-oldest ancestors. The next chapter, and so the next song, was about the embryology-presented through a chance meeting over a beer between Kowalevsky and ''Brother Straubinger'', a travelling journeyman whose literary career had begun in the drinking song of a Bavarian medical student some 50 years before (Reymond 1877, pp. 79-83). There is space here only for a selection of verses in which Straubinger recounts what happened after the St. Petersburg professor invited him out. Kowalevsky, whose report described amphioxus as starting to mate on warm May evenings between seven and eight, asks his acquaintance to appear on the beach ''behind Vesuvius'', ''sober'' and at half past seven precisely (Fig. 4).  Grows right through its intestines like a skewer.
Working up an appetite, Straubinger would not have minded hearing more over some spare ribs, ''because you don't never know what education will be good for'', but Kowalevsky sends him away hungry. Admirers and critics of Haeckel liked the rhymes (Hopwood 2015, pp. 142-143). A Catholic reviewer was pleased to see Darwinism's true colors exposed, and for an editor of the leading anti-Darwinist science magazine ''this food for the mind'' complemented the Christmas sweetness as perfectly as ''herring salad with Spanish pepper … a stomach upset by marzipan''. 11 Others saw Reymond as helping Haeckel, who was rumoured to have kept a copy in his jacket pocket (May 1909, p. 116), even though many verses cut nearer the bone than those about amphioxus. In Jena ''some of the best bits … were read out before the … zoology practical''. 12 English-speakers familiar with Haeckel's books, and the debates over them, enjoyed Reymond's verses too. In 1878 the British-born, Göttingen-educated Toronto palaeontologist and poet Edward John Chapman translated the first amphioxus song. His biologist colleague Robert Ramsay Wright had paid this animal much attention when reviewing the Anthropogenie for the local scientific society, the Canadian Institute. Like most professors, he found the book ''admirably lucid'' while regretting the ''assertive tone'', ''dogmatism'' and ''cavalier treatment'' of opponents (Wright 1876). Under the pseudonym Dr. Agorastes (''marketeer''), perhaps taken from Lucian's Sale of philosophies, Chapman dedicated his translation to Wright and the institute. 13 But Amphioxus and ascidian, our gelatinous ancestors ''imitated'' as much as it translated; compare what follows with my more literal rendition above. Chapman added information, colour and drama, accommodated with an extra line in each of three fewer verses, as he turned a drinking song into a lyric poem, a pictureless ''piece of jocose rhyming'' in the style of Samuel Taylor Coleridge, to be declaimed more than sung. 14 A slimy lancelet once lay Half-hidden in the golden sand Of Naples' blue and balmy bay-And thought-how pleasant, here, to-day Is Posilippo's strand.
But on the horizon's shadowy brim A horrid vision doth arise-A spectacled Professor grim! All things that creep, crawl, fly, or swim, Must he anatomize! A ''find'' his eager senses sniff-He stoops-he sees: with joy elate He grasps the creature in a jiff-And cries-now, I'll be jiggered-if It isn't vertebrate!

Hats off to amphioxus
Meanwhile, the German controversy over Haeckel raged on. In the Neue Freie Presse (New free press) of Vienna Vogt analysed Haeckel's metamorphosis from ''apostle'' through ''prophet'' to ''oracle''. Vogt ironically confessed as his own ''gravest sin'' that he had denied human kinship with ascidians and amphioxus and lampooned Haeckel's ''enthusiastic exaggeration''. He now protested against even more extreme ''hyperbolicization'' by exclaiming with reference to the demand of the Austrian tyrant defied by the Swiss patriot Wilhelm Tell: ''How long will it be before we have an edict that we must doff our hats to a jar of amphioxus, like in front of Geßler's pole with a hat on top!'' (Vogt 1877). In Reymond's verses, which developed this criticism, not long. Following the second book of the breviary, the more critical Exodus, a new instalment containing books three to five, Leviticus, Numbers and Deuteronomy, completed the Pentateuch in 1880. These still poked fun at the pedigrees, and now also satirized the latest debates by imagining the establishment of Haeckelism as the state religion and Haeckel's installation as high priest of an amphioxus cult. Leviticus, or ''the law for the prophets of the gospel of development'', opened with Steub's sketch of a kneeling Haeckel (Fig. 5) and this verse (Reymond 1880a, pp. 3-4):  The singer argued that if psalms must be sung, then to this little fish; if offerings made, then to the first animal ever to develop vertebrae, a ''headless-unconscious great deed of development'' by the ''ancestor and creator'' of human beings. There should be no blood sacrifice, however. Haeckel was presented as tempted to do away with some senior professors-he disliked ''Berlin biology''-but as choosing to give up dubious doctrines instead. In real life he maintained to the end, for example, the place of ascidians in the human stem-tree. If, when ordaining the Darwinist priests, Reymond's Haeckel detected any concession to creationism and teleology or scepticism towards recapitulation, he felled them with a lightning bolt and finished them off with ''bad jokes'' (Reymond 1880a, pp. 10-17). His pamphlet on freedom in science and learning slaughtered the traitors Abihu, that is the left-liberal pathologist Rudolf Virchow, who had opposed the teaching of evolution in the schools, and Nadab, alias Reymond (1880a, pp. 18-25) (Fig. 6). Peace came when, like Yahweh quashing the rebellion of the tribes of Israel by causing Aaron's rod to bud, Darwin ended his followers' rivalry by keeping evergreen only Haeckel's tree of ''gastrae', amphiox and ape''. 16 Reymond parodied Haeckel's cult, but reflected the consensus on the ancestral status of amphioxus.

This exquisite form
Having subsided in the 1880s, Darwinist debate revived in the following decade. From 1899 Haeckel's bestselling anticlerical synthesis Die Welträthsel, translated as The Riddle of the Universe, expanded the audience for science, took him to dizzying heights of international notoriety and fame, and created a market for a fresh English translation of The Evolution of Man (Hopwood 2015, p. 167). New readers also discovered the Laienbrevier, including in the US (Kellogg 1908). According to an ''anniversary edition'', Haeckel recommended it to students too busy drinking and fencing for lectures (Reymond 1912, p. 251). He still praised amphioxus as ''after man the most important and interesting of all vertebrate animals'', a claim his translator exaggerated by omitting the ''vertebrate'' (Haeckel 1903, II, p. 441;Haeckel 1905, II, p. 419; see also Haeckel 1874, p. 298;Haeckel 1899, p. 69). Even as speculation about ancestors was going out of fashion, many biologists agreed on the merits of ''[t]his exquisite form'' (H. F. Osborn in Willey 1894, p. ix).
The ''Amphioxus song'', produced in and for biological summer schools in the interwar US, rejoices in this classroom staple: A fish-like thing appeared among the annelids one day; It hadn't any parapods or setae to display. It hadn't any eyes or jaws or ventral nervous cord, But it had a lot of gill slits and it had a notochord.
Chorus: It's a long way from Amphioxus, It's a long way to us. … It was a long way from the German tradition and Reymond's Haeckelism to these more technical, less historical verses. But laughter over Haeckel's cult still echoes in biologists' amused pride in an animal which, for all his efforts, never quite became a household deity or even a household word. 17 This look at the public life of amphioxus in its early years of fame has sought, on the one hand, to do more justice to its dominance than accounts that have dwelled on controversy over the ascidian theory and then the diverse challenges to what long remained the dominant view. It has contributed, on the other, to appreciation of the aesthetic dimensions of Darwinism and of species choice. Running through some of the fiercest battles in the history of science are smiles at Haeckel's excesses easing acceptance that he spoke a core of truth, ancestor-worship that self-consciously imitated a religious cult, and affection for Naples as the site of discoveries that revealed ancient history along the Mediterranean shore.