74 /ONITID.E. 



I exclude from No. I. Ariophanta Icvvipes, in which the number 

 of the admedian teeth is so far less numerous than in any other 

 species of the genus, being only 8 on each side of the central 

 tooth, or 10 as compared with 23, and is thus abnormal. From 

 No. III. Euplecta I also exclude E. prceeminens (subspecies of 

 travancorica) and semidecussata, in which the radula formula is 

 22 .1 .22 and 21 . 1 . 21 respectively, and thus is like that 

 of the dextrorse section of Ariophanta, while their generative 

 organs approach those of Euplecta. Both these species range to 

 Peninsular India, and thus form a sort of link with the majority 

 of the Ariophantinae of that side. The generative organs in other 

 species of Arioplianta and Euplecta show an interesting develop- 

 ment of one towards the other. 



Species included in the above Genera. 



I. cysis, immerita, interrupta, bajadera, intumesctns, dalyi 



(cysis var.) : = 6 species. 



II. belanyeri, bistrialis, ceraria, solata^ tranquebarica, madaras- 

 patana, *ligulata, eeylaiuca, Juliana = ga)ioma, basileus, 

 chenui : = 11 species. 



III. *layardi, phidias, sldplayi indica ?, partita, prestoni, 

 *subopaca, mysorensis, binoyaeusis, liypliasma, gardeneri, 

 subdecussata, colletti : = 12 species.] 



Genus RATNADVIPIA. 



Ratnadvipia, Godwin-Austen, Proc. Mai. Soc. iii, 1899 p. 253 ; id. 

 Mol. Ind. ii, 1899, p. 93 ; Collinge, Jour. Mai. 1901, viii, p. 64. 



Type, R. irradicuis^ Pfr. 



llaiige. Ceylon. 



Shell Vitrina-\ike, with few whorls, thin, not polished above, 

 the outer whorl large. 



Animal large, much larger than the shell. Mantle-edge large, 

 surrounding the shell and partly covering it : both the right and 

 left shell-lobes produced posteriorly into tongue-like expansions ; 

 dorsal lobes greatly developed, the left dorsal lobe in two parts. 

 The dorsurn of the body just behind the shell is flat, but it is 

 sharply keeled behind. Caudal extremity truncated; mucous pore 

 large. Peripheral groove double. Sole with a median groove 

 (not always conspicuous), but not divided into median and lateral 

 tracts. 



Kadula broad, with numerous teeth in each row ; the formula 

 is 204 . 23 . 1 . 23 . 204 (227 . 1 . 227). The median band of large 

 teeth is very broad, the teeth composing it are simple without 

 lateral cusps ; the numerous laterals are bicuspid, except the outer 

 marginals. Jaw with a concave edge without median projection. 



* According to Semper. 



