1871.] F. Stoliczka— Notes on Terrestrial Mollasca. 229 



the whorls above so very tumid, that the peripherical keel on the 

 last whorl instead of being near the upper edge conies to be situated 

 nearly in the middle of the whorl. The aperture is more or less 

 deflected, of a transverse, elongately oval, shape, with the inner 

 lip generally conspicuously thickened and slightly emarginated. 



The species was originally described from Tavoy. It is not 

 uncommon about Moulmein on the limestone hills at Damotha and 

 eastward on the Gayin river, but I have not obtained a living speci- 

 men of it. Major Godwin- Austen collected it also in the North 

 Cachar hills. "Wallace quotes it (doubtfully) from Celebes, but 

 Martens, (Preusis. Exped., p. 391) seems to question the correctness 

 of the locality. 



Hanley and Theobald, in their Conch. Indica, give a rather poor 

 figure of Merguiensis, but what is figured as gahata, Gould, appears 

 to me to represent a shell of exactly the same type as Gould's 

 procumbens which is identical with Benson's delibrata. 



Fam, ZONITID^E. 



The animals of this family are characterized by the invariable 

 presence of a mucous gland, situated at the truncate, posterior end 

 of the foot ; above the base of the sole runs a distinct lateral line, 

 or a row of enlarged tubercles, between the gland and the mouth ; 

 the jaw is smooth, or finely concentrically striated ; outer teeth 

 of the radula slender and generally bicuspid at the end, except the 

 very last ones which are often simple, styli-form. 



In the muscular, digestive and nervous systems the Zonitid^e 

 do not differ from the Helicid^e, but there is usually a slight dif- 

 ference to be observed in the reproductive organs. In the latter 

 family the so-called arrow or amatorial sac* (glandula mucosa 

 cum sagitta amatoria) is short, with numerous thin appendages ; 

 in the former it is either simple, or sometimes altogether absent. 

 If present, it appears to be an important organ during copula- 

 tion. It is generally of a cylindrical shape and of a tough, mus- 

 cular structure, attached by a special retractile muscle, enclosed 

 in a tubular sheath and terminating with a pointed papilla or flao-el- 



* Or dart-sac of some English authors. 



