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 Lovén of Stockholm in the young of Kellia 
rubra, but as these are viviparous, the metamorphosis takes place 
before extrusion. Professor Lovén has, however, traced the same 
metamorphoses in the young of Modivla discors (marmorata), 
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. Different 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. Helia Ampulla, 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 inflato, 
apice convexo-depresso ; apertura parum obliqua, rotundato-ovali, 
imtus concolori, peristomate acuto, margine columellari arcuato, 
tenui, intrante. 
Diam. maj. 42 mill., minor 31 mill., axis 30 mill. 
Hab. Khoorda Ghat, in montibus Nilghiri dictis, Indize Meridionalis. 
Teste Jerdon. 
The strong horny epidermis occupies nearly as much of the 
