50 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY. 



anterior portion (Fig. 2), present in thi'ee specimens I have looked at, 

 is of importance, for it is of a different nature altogether from the 

 division of the sole of the foot as seen in genera of the Zonitidte, and 

 it is not a feature in the foot of the true Helicidse. If this character 

 should not be found in Trachia mperdla, delihrata, etc., vdtata cannot 

 then be included with them. It should also be ascertained how far 

 other Indian species of Helicidae agree in this respect with vittata. 

 Albers' name Eurystoma, used in this paper, I am informed cannot be 

 retained, being preoccupied, but this is not of importance particularly, 

 should the animal of vittata be finally found to be similar in all 

 respects to that of asperella, the type of Trachia^ and this species has 

 yet to be examined. In searching through the Helicidse in Semper's 

 work, " Reisen im Archipel der Philippinen," for species with similar 

 characters, I was struck by the great and interesting similarity of the 

 generative organs of Buliminus [Petraus) Siamensis, Redfield (pi. xiv, 

 fig. 15), and also of the radula (pi. xvii, fig, 23) with those of vittq,ta. 

 I have lately been working at the anatomy of Glessula^ and, as shown 

 in the species tenuispira, Benson, there is no great difference in its 

 generative organs and those of Eurystoma. Although the shells of 

 these genera are dissimilar in every respect, from a phylogenetic point 

 of view the animals of Indian forms of the Helicidae, such as those 

 under review, and as far as they are known, more nearly resemble 

 those of species of Stenogyra and Buliminus than they do the true 

 Helices of the Palsearctic region. This, however, may be only parallel 

 development on similar lines. It is very apparent that Indian forms 

 of Helicidse have started from a very distinct and separate stem to that 

 of their more western congeners. 



EXPLANATION OF PLATE IV. 



Aperture, showing mantle-lobes and sole of foot. X 4'5. 



Sole of foot, anterior part, x 4"5. 



Anterior portion of visceral sac. 



Central and admedian teeth of the radula. 



Jaw. X 24. 



Renal organ, heart, etc. 



Buccal mass with salivary glands. 



Outer teeth of the radula, 34th to 36th, and 46th to 47th. 

 10. Penis, viewed from different sides. 

 , Portion of the genitalia, spermatheca, ovotestis, and albumen gland. 



auricle. rts.ap. respiratory apertui-e. 



renal organ. s.ffd. salivary gland, 



mantle -edge. u. ureter, 



pulmonary vein. v.d. vas deferens, 

 retractor muscle. 



