13 171 



gill-cavity was seen anteriorly outside of the vulva a white dotted, thin layer, the sub- 

 branchial gland , while the bottom otherwise was black spotted , and showed the liver and 

 two transverse windings of the intestine. 



The central nervous system (flg. 2) was very similar to that of Notarchus l ). 

 The cerebral ganglia somewhat lengthily joining each other, the pleural ones somewhat 

 removed from the former and much smaller. Between the latter the two visceral ganglia 

 were seen adjacent to each other; the right one of these ganglia was directly adjoining the 

 (right) pleural one , while the left one was connected with the (left) pleural one by a 

 distinct connective. The pedal ganglia (fig. 2 c) , which were connected by a short com- 

 missure , were little smaller than the cerebral ones. The buccal ganglia were roundish, 

 connected by a quite short commissure. — The nerve -cells reached to a diameter of up 

 to 0-22 mm . 



The eyes had a diameter of 0'28 mm ; they were imbedded in the hypoderm, and 

 were copiously provided with black pigment. The otocysts were attached to the pedal 

 ganglia, of a diameter of - 12 mm , filled with not very numerous otoconia. The tufts of 

 the upper surface of the animal (figs. 31,32) were of the common structure of the skin, 

 only with a much smaller number of pigment cells. The mentioned subbranchial gland 

 showed closely packed globular gland-cells, mostly of a diameter of (V08 — - 16 mm . 



The buccal tube had a length of l mm ; it was externally gray, internally black 

 dotted. — The bulbus pharyngeus was short pyriform, of a length of 4 mm , by a breadth 

 and height of 3 mm , of a yellowish white colour, dark-gray in the region of the pharynx, 

 the end ol the thick radula-sheath projected posteriorly at the lower side. A great median 

 stripe of the (blackish) palate was covered with irregularly close packed palatal hooks 

 (figs. 34, 35). These hooks were horny, highly compressed, their hinder edge was some- 

 what thicker; along this edge they had a length of 0'06 mm by a greatest height of up to 

 0025 mm , and the gradually rising hook continued in a short point turned towards the 

 pharynx. The yellowish mandible plates were short reniform, of a breadth of up to 

 0-gmm formed of closely crowded, cylindrical elements (fig. 36) reaching to a height of up to 

 0-1 6 mm , by a breadth of up to 0025 mm . The walls of the buccal cavity were black. The 

 short and broad tongue was blackish, to which colour the shining yellow colour of the 

 radula formed a strong contrast. The foremost third part of the radula seemed to be 

 wanting (fig. 3), and the remainder was tapering anteriorly, and provided with much 

 damaged plates. In the radula were seen 14 series of tooth-plates (counted at the outer 

 edge), further backward in the short sheath (fig. 3 a) 8 fully developed ones and 3 not fully 



') A. Vatssière, rech. — sur les moll, opisthobr. I. Tectibranchcs. (Ann. du musée d'hist. nat. de 

 Marseille. Zool. II, 3). 1885. pp. 91 -97. pi. 4, figs. 94, 95. 



22" 



