106 Transactions of the South African Philosophical Society. 



the two largest had a breadth of 16 and a height of 8 mm. They 

 were uniformly coloured whitish ; on the back rather spread short 

 0*5 mm. high conical prominences ; the shell shone white through 

 the mantle, but always (on account of the strong contraction) broken 

 in pieces. The form of the animal as usual ; so too, as far as could 

 be determined, the thin shell. 



The bulbus pharyngeus of usual form, 6 mm. long ; the rasp-sheath 

 in two of the three more closely examined (female) individuals rolled 

 up to the right, in the third (male) to the left side. The mandibular 

 plates, 2*5 mm. long, of about the usual form, but the brownish 

 masticatory part not separated by an actual furrow from the 

 yellowish remainder ; the anterior narrower margin (in the three 

 individuals) produced in a strong point (fig. 13). On the yellowish 

 rasp 16-17-20 series of plates, in the sheath 25-40-42, the total 

 number of rows being thus 41-57-62 ; the end of the sheath very 

 little swollen, rounded behind. The thicker part of the lateral plates 

 yellow ; the rest as well as the median plates nearly colourless. The 

 breadth of the median plates 0*25 mm., the length of the lateral 0*52. 

 The median plates with curved anterior margin with pointed hook 

 and with about 10 fine denticles on its sides, the posterior margin 

 straight (not bifid) (figs. 14, 15). The lateral plates of usual form, 

 the upper margin of the hook with 8-20 fine denticles, the other 

 with 6-8 coarser. 



The liver grayish brown. The large ovarium yellow. The penis 

 (fig. 16) 7 mm. long, somewhat flattened, always (by 10 individuals) 

 of quite the same form. 



The largest (male) individual 4 cm. long by a breadth of 3*3 and a 

 height of 2 ; when living it was white ; the back was somewhat 

 nodulous ; the penis quite as described. The shell very thin, 

 broken. 



The bulbus pharyngeus 7 mm. long, the rasp-sheath rolled up to 

 the right. The mandibles nearly as above. In the rasp 17 series of 

 plates, in the sheath 49, the total number of rows being thus 66 ; the 

 plates quite as above. 



3. Marsenia leptoconcha, B. n. sp. 

 PI. IX., figs. 17-20; PL X., figs. 1-2. 



One male specimen was procured off Cape Point (E. J, N. 

 36 miles) from a depth of 700-800 fms. from green mud bottom by 

 shrimp -trawl. 



The specimen resembled, preserved in formalin, a somewhat 



