The fine structure of the branchial heart appendage of the cephalopod Octopus dofleini martini
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- Witmer, A. & Martin, A.W. Z.Zellforsch (1973) 136: 545. doi:10.1007/BF00307370
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The branchial heart appendage of Octopus dofleini martini has been investigated electron microscopically. This organ is dominated by peripherally lobed blood sinuses. It contains free hemocyanin (often aligned in rows), amoebocytes, endothelial cells, and muscle cells which occur mainly in connection with neurons. The neurons are often exposed to the blood. The blood sinuses are enclosed by a basement membrane which contains collagen equivalents and fine fibrillar elements. The sinuses are covered by two different epithelia: 1) the epithelium in the caoity of the appendage consisting of irregularly shaped cells with processes, the so called (∼ 30 μ high) podocytes, and 2) the epithelium (∼ 40 μ in height) on the surface of the organ, which is composed of two parts: a) a “lacuna”-forming portion directly adjacent to the basement membrane, which is topped by b) a continuous tissue portion with occasional “lacuna”-canals. The intercellular spaces of the inner and outer epithelium are connected. The structures of these epithelial cells are discussed in relation to the formation of the pericardial fluid.