XV. MOLLUSC A, I: RATHOUISIIDAE. 



By Ekendranath Ghosh, L.M.S., B.Sc, Assistant Professor 

 of Biology, Calcutta Medical College. 



(Plates x-xiii). 



Two species of this family were obtained by Mr. Kemp in the 

 Abor foot-hills, both new to science. I have described them under 

 the following names : — 



Atopos [Podangia) kempii and Prisma aborense. 



Atopos (Podangia) kempii, n. sp. 



Two slugs, obtained at Kobo (400 ft.), belong to a new 

 species which may be named Atopos {Podangia) kempii, and 

 briefly defined as follows : — 



Notum of light straw-colour, being dirty in its upper two- 

 thirds, with an irregular network of dark blue lines (mostly passing 

 diagonally in two directions), with dark elongated dots at the 

 points of intersections. Surface of notum finel}^ and uniformly 

 granulated, with minute dark blue dots in the interspaces of the 

 network in addition. Ommatophores and lower tentacles slaty- 

 blue. Keel well- developed and prominent in the posterior three- 

 fourths of the length of the body. Foot light yellow and extend- 

 ing beyond the inflexed posterior margin of the mantle, but not to 

 its extreme posterior end. Length of notum 5 "5 cm., breadth 7, 

 height '9. Female genital aperture I'O cm. from the male genital 

 aperture. 



External Characters. 



General. — The animal is elongated, limaciform. The body is 

 flattened from side to side, having the shape of a narrow-based 

 isosceles triangle in transverse section. The thickest part of the 

 body lies at the junction of the anterior one- fourth and posterior 

 three- fourths of its length. At that position the surface of the body 

 presents a rounded prominence on each side, just below the keel. 

 The prominence is more marked on the right side than on the left. 

 The surface of the mantle (notum) is finely and uniformly granulat- 

 ed. The keel, in the middorsal line, is rounded and not very promi- 

 nent in front of the thickest part of the body ; it ends a little behind 

 the anterior end of the mantle, which forms a hood over the head. 

 Behind the anterior one-fourth of the length of the body, the keel 

 forms a distinct vertical crest flattened from aide to side, and 

 extends to the posterior end of the mantle, gradually lessening in 



