28 



pass into aculeate pointed marginals. Jaw curved, with a small 

 median projection. 



The egg of A. Icevipes is elliptical, longitudinally sulcated, 

 enclosed in a tough membrane, and 4 to 5 mm. in length, 4 to 4| 

 in diameter. That of A. interrupta is similar. 



This genus is now regarded as confined to the Indian Peninsula 

 and Ceylon, various Burmese and Malay sinistral forms, formerly 

 referred to it, being assigned to other genera ; whilst a considerable 

 number of dextral Southern Indian and Ceylonese species, formerly 

 classed under Xesta and Hemiplecta, or separated as Cryptozona, 

 Xestina, or Nilgiria, are now united with the typical sinistral 

 forms of Ariophanta into a single genus, the animals being very 

 similar in their general anatomy. 



[Key to Species of Ariophanta. 

 Section I. Typical, sinistral. (ARIOPHANTA.)] 



A. Shell perforate or very narrowly uinbilicated. 



a. Shell solid, not horny. 



a'. Radula with a narrow central band of only 

 17 median teeth ; the left dorsal lobe divided 



into two distinct parts Icevipes. 



laidlayana. 

 kadapaensis. 



b. Horny, brownish, more or less translucent. 

 b'. Depressed. 



a". JRadula with broad central band of 35 to 



55 teeth interrupta. 



immerita. 

 b". Globose bajadera. 



intumescens. 



B. Shell openly and deeply umbilicated cysis. 



Subsp. dalyi. 



thyreus. 

 Subsp. hetercea. 



Section II. Dextral. (CBYPTOZONA ?) 



A. Colour uniform or nearly so, no spiral bands of 



colour. 



a. Decussated above. 



a 1 . Radula with broad band of median teeth ; left 



dorsal lobe undivided semirugata. 



belangeri. 



b. The whorls transversely striated, not decussated . albata. 



sisparica. 



novella. 



ceraria. 



B. Shell spirally banded with colour more or less 



distinctly. 



a. Decussated but not grooved ligulata. 



bistrialis. 

 basikssa. 

 yardeneri. 



