406 Mr. W. T. Blanford on a new Helix. 



Fig. 32. The same, more advanced stage, showing that the opaque portion 

 or body lias withdrawn itself within the dermal membrane 

 or ectoderm, leaving the latter suspended on spicules, which 

 project in bundles from the former, and thus producing the 

 angulated surface first seen in fig. 30, now extend nakedly a 

 little beyond it, leaving a cavity or open interval between it 

 and the opaque body : a a, opaque portion or body ; h b, bundles 

 of spicules ; c c, dermal membrane or ectoderm ; d d, its cavity. 

 Compare this and the following figures with my illustrations 

 to the paper "On the Ultimate Structure of ISpongilla'' ('Annals,' 

 1857, vol. XX. p. 21, plate i.), in which it will be seen that this 

 dermal membrane is my " investing membrane," and the interval 

 between it and the opaque body its "cavity," in Spongilla, also 

 that the pores are situated in the former. 



Fig. 33. The same, lateral view ; a, vent, osculum, or termination of the 

 end of the excretory branched canal-system, now fully developed. 



Fig. 34. The same, embryo torn to pieces in sea-water on a glass slide, 

 and placed under ^-inch compoimd power ; showing that the 

 skeleton-structure, now consisting of the spicules bundled to- 

 gether and held in position by cornified sarcode, is fully de- 

 veloped into the form of that of the parent, the dermal mem- 

 brane or sarcode, and also the spongozoa and ampuUaceous sacs : 

 a a, skeleton-structure ; b b, sarcode of the opaque or parenchy- 

 matous body charged with fuUy developed ampuUaceous sacs, 

 separate spongozoa, cells of different sizes below these, and 

 granules ; c c, ampuUaceous sacs ; d, spongozoon separate ; 

 e e, dermal or " investing " membrane ; //, its cavity ; g, more 

 magnified view of monociliated spongozoa. 



LI. — Descnjjtion of a neio Helix from Southern India. 

 Bj W. T. Blanford, F.K.S. 



An immature specimen of a very fine species of snail allied 

 to Hemiplecta hasileus (Bs.) was sent to me some years since 

 by Colonel Beddome, to whom we owe so many discoveries 

 amongst the numerous and peculiar molluscan forms inhabit- 

 ing the forests of the Southern Indian hill-ranges. I named 

 the species after the discoverer, but on further examination 

 resolved not to describe it, as the characters taken from the 

 young shell approached so closely to those of H. hasileus and 

 //. Chenui that there must have been difficulty in recognizing 

 it. Kecently Colonel Beddome has shown me a full-grown 

 .specimen, which he has presented to the British Museum ; and 

 from this I have taken the following description : — 



Hemiplecta Beddomeiy sp. n. 

 H. testa aperte perforata, convexo-depressa, tenuiuscula, oblique 

 strial.a lineisque impressis spiralibus decussata, sulcis brevibus 

 obliquis subspiralibus rugata ; subtus la;viore, nitidula, striis radi- 



