MOLLTJSCA OF INDIA. 205 



in the jaw of Thymnota guerini (fig. 4) the resemblance is still 

 greater. 



The teeth of the radiila (fig. 2 d) are thus disposed : — 



12 . 9 . 1 . 9 . 12 or 21 . 1 . 21. 



The centre tooth is small, on a narrow oblong plate ; the plates of 

 the admedian teeth are nearly square, and there is an indication of 

 a duplication followed by fusing of parts, for the square plate is 

 divided into a long inner oblong portion and a shorter outer oblong 

 portion having a well-defined rounded upper outer angle. 



At the 10th tooth the very long inner cusp of the 9th tooth 

 becomes bicuspid into blunt rounded points, the bicuspid form with 

 a single small cusp outside it continues to the outermost teeth 

 (vide the 19th). This type of radula, I may here note, is peculiar 

 to the genera Thysanota, Si/Jcesia, and Philalanka, to a greater 

 or less extent with modification of the central and admedian 

 teeth. 



Subfamily Duegellin^. 

 Genus Durgella. 



(Continued from Vol. II. p. 70.) 



Durgella rogersi, n.sp. (Plate CXV. figs, 4, 4 a; Plate CXVI. 



figs. 7, 7 a.) 



Locality. Paphunta Valley, South Andamans (Gr. Rogers, Esq., 

 1906). B. M. Collection. 



Shell globose, very thin, membranaceous : it was impossible to 

 remove the animal preserved in spirit without tearing it. Whorls 3|, 

 colour pale straw, apex flatly rounded. 



Animal about 20 mm., contracted in spirit. Foot long behind, 

 pointed, keeled, narrow ; sole divided ; peripodial grooves with 

 parallel streaking running from them to the margin of the foot. A 

 fairly large rounded right shell-lobe rising on the side of the right 

 dorsal lobe ; the left shell-lobe smaller than the right, rounded on 

 the margin ; both shell-lobes somewhat thickened, pale-coloured, 

 unmarked, and smooth. 



The genitalia were not, unfortunately, got out in a state for 

 description. The penis is simple, like that of I), levictda ; no 

 amatorial organ seen. 



Jaw very thin, almost straight in front, only a slight convexity 

 in the middle. 



Radula consists of an enormous number of teeth ; there are at 

 least 500 in the row, and 70 roAvs can be counted. It was got out 

 in nearly a perfect state, but the filmy edges got folded under it ; 



