230 F. Stoliczka— Notes on Terrestrial Mollusca. [No. 3, 



lum. The internal cavity is often filled with hardened particles 

 of various shapes. Although during copulation an intromissile 

 organ, it can only be considered as an organ of irritation, while the 

 true penis is represented by a simple enlarged tube of the termi- 

 nal part of the seminal duct (vas deferens). This is mostly the 

 case, whenever the amatorial sac with its papilla is well developed. 

 Some most remarkable organs, apparently modifications of the 

 amatorial sac will be noticed in the genus Sesara and in Mac- 

 rochlamys \_Burgella\ lionesta. I hope to return to this subject 

 at some future date and give a revised list of the Indian 

 genera belonging to the present family, but many more animals 

 must yet be examined, before reliable materials for purposes of 

 classification can be obtained. 



For the present I shall confine my remarks to the following 

 genera, Rotula, Conulema, Sesara, Macrochlamys with JDurgella, Micro- 

 cystis and Sophina. Of other forms of Zojstitidje, common about 

 Moulmein, I have omitted Jlelicarion, having the intention of 

 examining this genus in connection with several other allied 

 forms from the Khasi-hills and from the Himalayas at an early 

 date. 



With reference to the organs which are useful in the grouping 

 of the ZoisrrTiDiE, I would especially draw attention to some variabi- 

 lities in the genital apparatus. The presence or absence of an arrow, 

 or amatorial sac, has been considered as an important generic distinc- 

 tion. I have repeatedy satisfied myself, that it is not so, and more- 

 over that references to the form and shape of the genital organs 

 must be very cautiously made. When animals are examined, it is 

 very important to know whether they are full grown or adolescent, 

 or very young. In each of these cases the form of the genital organs 

 may be very different, as will, for instance, be found noticed 

 in the genus Sesara. Again the size and development of certain 

 parts of the genital system vary greatly according to the season of 

 the year, &c. 



In speaking of the different organs in the general anatomy of 

 the animals, I have mostly employed terms which have come into 

 general use in anatomical publications. The arrow sac, (or dart-sac 

 of some English authors) I have often termed amatorial sac, be- 



