Mr. W. H. Benson on new species of Helices. 213 



of development further observations were unfortunately arrested 

 by the death of the whole colony, in consequence of the water 

 becoming impure, and my situation at a distance from the sea 

 preventing my getting an immediate fresh supply. The whole 

 period that I had kept them was not above five or six days, so 

 that their development had been pretty rapid. After the death 

 of the animals the shells remained at the bottom of the glass. 

 They were of an elliptical form, straight at the upper margin, 

 where they were attached, though the hinge did not appear to 

 be yet formed : the whole, excepting in the elongated form, had 

 very little resemblance to the adult shell. 



The process which this embryo undergoes in the course of 

 development is similar to what has been observed in the fresh- 

 water bivalves by some continental naturalists, as well as more 

 recently by Professor Loven of Stockholm in the young of Kellia 

 rubra, but as these are viviparous, the metamorphosis takes place 

 before extrusion. Professor Loven has, however, traced the same 

 metamorphoses in the young of Modiola discors {marmoratd), 

 commencing about the third day after the deposition of the 

 spawn. In the present instance the process likewise commenced 

 about the same time after extrusion, but from the artificial po- 

 sition in which the animal had been placed, there is a possibility 

 that the birth may have been premature, especially as some spe- 

 cies of the family are known to be viviparous. 



EXPLANATION OF PLATE VI. B. 



Fig. 1. Montacuta ferruginosa, magnified. 

 Fig. 2. Anterior portion of the cloak more highly magnified. 

 Fig. 3 to 7. DiiFerent stages in the development of the embryo. 

 Fig. 8. Shell in the embryo state. 



XXI. — Characters of several new East Indian and South African 

 Helices, with remarks on some other species of the Genus occur- 

 ring at the Cape of Good Hope. By W. H. Benson, Esq. 



1. Helix Ampulla y nobis, n. s. 



T. imperforata, oblique globoso-ovata, tenuissima, irregulariter pli- 

 cato-striata, striis antice obsoletioribus, transverse et oblique ru- 

 gosa, olivacea ; anfractibus 3 velociter crescentibus, ultimo inflate, 

 apice convexo-depresso ; apertura parum obhqua, rotundato-ovali, 

 intus eoncolori, peristomate acuto, margine columellari arcuato, 

 tenui, intrants. 



Diam. maj. 42 mill., minor 31 mill., axis 30 mill. 



Hab. Khoorda Ghat, in montibus Nilghiri dictis, Indise Meridionalis. 

 Teste Jerdon. 



The strong horny epidermis occupies nearly as much of the 



