56 



longitudinally folded and opens widely into the stomach. The posterior part of this latter has a 

 strong layer of circular muscles. In the stomach are iour large horny plates, two dorsally and 

 two ventrally. Between the two dorsal plates, a httle more distally, is situated a fifth triangular 

 plate. The dorsal position of this posterior plate is remarkable, for in the Cavoliniidae it is 

 situated on the ventral side. Pelseneer does not say whether this plate of the Cymbuliidae 

 is dorsal or ventral. 



The liver extends very far forward; it opens into the stomach, immediately behind the 

 horny plates, by a very large opening, situated a little to the right of the median line. This 

 wide hepatic duet soon divides into two. According to Gegenbaur ^) there are from three to 

 six canals. Souleyet ") mentions: "un conduit assez large qui s'ouvre a l'origine de l'intestin". 

 Finally Pelseneer has seen two hepatic ducts. After receiving the hepatic duet the stomach 

 exhibits dorsally a large and short coecum, in which the brown villi of the stomach extend. 

 A long intestine is coiled up in the liver and in the gonad; its walls are extremely thin, 

 consisting only of one layer of flat ciliated cells. The intestine is curved in the same way as 

 in the Cavoliniidae; the anus, however, is quite ventral, scarcely reaching the median line, 

 whereas, as one knows, in the Cavoliniidae the anus is situated at the left side. 



The generative organs. The gonad is especially developed on the left side, but 

 distally it occupies the whole posterior portion of the visceral mass. It is composed of lamellae 

 as in the Cavoliniidae; the histological structure too is nearly the same, but I found the ova 

 in the central portion; peripherically the spermatozoids cling together. At the anterior part of 

 the gland, at its concave side, a narrow duet proceeds from it (PI. III, fig. 95, a). This duet, 

 with occasional dilatations, surrounds the accessory genital glands, which are situated before 

 the stomach, on the ventral side. The large muciparous gland {ó) is strongly folded, especially 

 on the ventral surface ; a small albuminiparous gland (c) may be distinguished at the right 

 side. The latter shows a peculiar external structure of bunch-like elevations. Between the two 

 glands a receptaculum seminis with a rather long duet {d) is situated, and here too a vas 

 deferens (e), soon becoming a spermatic groove, arises. 



The penis opens in the middle line, behind the tentacles. The walls of the copulatory 

 organ are very strongly folded, and there is an epithelium of high cells with deeply staining nuclei, 

 which is so characteristic of the Cavoliniidae, but no horny stylet in the cavity of the penis. 



The central nervous system. A short description may be sufficiënt, as the 

 nervous system has already been recognised in its peculiarities by Pelseneer ■'). 



The cerebral ganglia, situated at the side of the oesophagus as in all Thecosomata, and 

 united by a long .supra-oesophageal commissure, are rather elongated (PI. III, figs. 97 — 98, c). 

 The pedal ganglia (/) are the largest, coloured whitish, and nearly circular. The second pedal 

 commissure (figs. 96, 98, a) has not been figured nor menticjned in this genus by any previous 

 author. In the arrangement of the visceral ganglia (v.J^.z'.) is shown again the phylogenetic 

 affinity to Peraclis. These ganglia are three in number and disposed symmetrically ; the two outer 



1) Untersuchungen über Pteropoden und Heteropoden, p. 48. 



2) Voyage de la Bonite, vol. II, p. 234. 



3) L. s. c, p. 24 — 26, pi. III, figs. 10 — II. 



