The Opisthobraiichiata of South Africa. 21 



The form of the animal as in other Aclesise, a Httle pointed 

 behind, the back rather vaulted. The baciiside everywhere very 

 uneven, covered with simple and compound papillae, for very large 

 part confluent to numerous undulating crests and tufts covered with 

 smaller papillas ; on the sides of the back proper the crests some- 

 times coalesced in a kind of ridge and behind on each side over the 

 tail in a larger prominent knot. The rhinophores and the tentacles 

 also covered with papillae. The border of the foot-wings convex, 

 their inside even. The seminal furrow distinct. The foot a little 

 broader in front, with a small median notch. 



On the floor of the gill-cavity no mantle plate, and the organs were 

 uncovered (PI. III., fig. 16). On the left side the long white kidney 

 with a pore on its hinder end (fig. 16). To the right of the kidney 

 the strong curved gill, of dirty yellowish colour, with grayish or 

 blackish rhachides (fig. 16). Stretched out, it had a length of about 

 2 cm. by a breadth and height of 4-5 mm., about its half not 

 attached; it contained about 15-18 groups of lamellae (fig. 1). 

 Behind the first part of the gill the thick upwards turned anal 

 papilla with black strige and several (about eight) rather prominent 

 knots around the opening (fig. 16c). Before the gill to the left the 

 somewhat black dotted pericardium and to its left, under the brown 

 part, the blood-gland ; the vulva as usual. 



The central nervous system as usual in the Notarchidae. 



The mouth tube 3-4 mm. long. The bulbus pharyngeics short- 

 pyriform with the thick radula-sheath projecting a little on the lower 

 side behind ; 7'5-9 mm. long by a breadth of 5-6"5 and a height 

 of 4-5-6, whitish. The mandibles longish, broader upwards, 

 2-5-3 mm. long by a breadth up to 0-75-1, dark red-brown 

 (fig. 17) ; their elements nearly cylindrical, reaching to a height of 

 0-2 by diameter of 0-020 mm. (fig. 18). The walls of the cavity 

 of the mouth dark red-yellow, darker on the palate, whose side parts 

 showed the usual covering of closely set compressed hooks of a 

 height up to O'l mm. (fig. 19) ; this covering is continued to some 

 extent up into the pharynx. The rasp of the short and broad tongue 

 (fig. 20) dark brown or brownish yellow, of a length and a breadth 

 of 3-4 mm., containing 20-28 series of teeth, in the sheath 15-18, 

 the total number of series thus being 35-46. The number of lateral 

 plates on each side of the median about 36-40. The plates reddish 

 bi'own at the basal parts, elsewhere yellow, the breadth between the 

 legs of the median plates nearly 0-20 ; the lateral reached a height 

 of 0-30 mm. ; that of the four outermost was mostly about 0-12- 

 0-16-0-20-0-24. The median plates of the usual form (fig. 21), with 

 3-4 denticles on each side of the pointed hook ; the first lateral 



