25 



Family ZONITID^. 



Subfamily ARIOPHANTIN,E. 



[The Ariophantince form a very distinct subfamily of the Indian 

 Mollusca, and are almost exclusively confined to the Peninsular 

 area and Ceylon ; only two species are found extending a short 

 distance northward into the Gangetic delta, but have not been 

 recorded from that of the Brahmaputra River. The largest Indian 



rmp 



Fig. 16. Ariophanta l&vipes. 



A. Genitalia. X 3. 



B. Ditto, part of, showing sperrnatheca. 



0. Portion of male organ near junction of vas deferens, showing position of a 



spermatophore. 

 D. Terminal end of the amatorial organ or dart. 



am.or. Amatorial organ or dart. 

 crp. CcBcum musculi retract oris 



penis of Semper. 

 d. Dart. 



gen.ap. Generative aperture. 

 k. Kale-sac. 

 ov. Oviduct. 



p. Penis. 



rm. Eetractor muscle. 

 rmp. Eetractor muscle of penis. 

 sp. Spermatheca. 

 v. Vagina. 

 vd. Vas deferens. 



land-shells belong to this subfamily. All are large and fine forms, 

 both sinistral and dextral ; they vary much in form from solid, 

 turbinate, to thin and very globose shells, and to others Helicarion- 

 like, thin, diaphanous, and membranaceous. 



The generative organs have three marked characters, viz., the 

 penis caecum (" caecum musculi retractoris penis " of Semper), 

 to which the retractor muscle is attached; a very small pear- 



