The Telencephalon of Snakes

Abstract

Reptiles, as a group, are most interesting subjects for the study of telencephalic development, because it is in reptiles that the differentiation of cortical regions first becomes obvious. The relative simplicity of the reptilian telencephalon and its position intermediate between amphibian and mammalian telencephalic development offer further inducements to its study. Of particular interest to students of development of the central nervous system and those attempting to define homologous structures is the observation that the development of the reptilian brain parallels the development of mammalian brains (Warner, 1946) and that many similarities exist between the final adult reptilian telencephalon and intermediate stages of mammalian telencephalic ontogenetic development (Humphrey, 1967). Interestingly, reptiles differ among themselves considerably and must be considered an exceptionally heterogeneous group. It is therefore somewhat surprising that with the exception of a few scattered reports (Meyer, 1892, 1895; Rabl-Ruckhard, 1894; Edinger, 1896; Ariëns Kappers and Theunissen, 1908; DeLange, 1911; Rose, 1923; Ariëns Kappers et al., 1960), one serious series of investigations (Warner, 1931, 1946, 1947), and a short paper by Carey (1967) little attention has been paid in the past to the study of the ophidian telencephalon. It has only been within the past 3–4 years that experimental work has been reported on the telencephalon of snakes. It will become clear as this chapter progresses that the major current work on the ophidian telencephalon is occurring in Dr. Philip Ulinski’s laboratory and my own.