HELIX-AM PELITA. 45 



subsimple, its upper margin prominent in the middle, thin, apparently 

 scarcely expanded; columellar edge slightly thickened, expanded 

 and reflexed. (Smith.') Alt. 16, greater diam. 36, lesser 30 mill. 



Ankafana, Betsileo Province, Madagascar. 



H. (Macrocydis) covani E. A. SMITH, Journal of Conchology ii, p. 

 338, 1879 ; Proc. Zool. Soc. Lond. 1882, p. 381, t. 21, f. 10-12. 



This species was originally described from a single specimen which 

 did not illustrate the full size attained by adult shells. The largest, 

 and apparently full-grown example, lately brought to England by 

 Mr. Cowan, has a greatest diameter of 45 mill., is 33 across at the 

 smallest diameter, and 20 high, resting upon its base. The peristome 

 is not thickened or expanded on the upper margin, but is simple and 

 arcuate. (Smith.} 



H. GONOSTYLA Ancey, Le Naturaliste, iv, p. 119. This number 

 of Le Naturaliste is missing in the Academy library. 



Unfigured species of Ampelita. 



The following diagnoses are translated from the original ones of 

 Mr. Jules Mabille. In a group where the species are so critical as 

 in these Madagascar Helices, good figures or careful comparisons 

 with known species are essential for the recognition of new forms. 

 Diagnoses without such comparisons are worse than useless. Con- 

 chologists should give such work precisely that measure of recogni- 

 tion which has been given by its author to the real needs of descrip- 

 tive zoology. The practice of publishing such literature in this age 

 of inexpensive illustration is obviously inexcusable. It would seem 

 that in order to prevent, as far as possible, the identification of their 

 species, Mr. Mabille and his colleagues invariably neglect to men- 

 tion the subgenus or section of the immense genus Helix, to which 

 their supposed novelties belong. 



H. porcaria Mabille. Shell sub-broadly umbilicate, depressed- 

 conical, solid, thick, hardly shining, white under a dull black epider- 

 mis, subregularly ribbed-striate ; spire convex-conic, nearly destitute 

 of epidermis; apex obtuse, rugose; whorls 5-5 , convexly sloping, 

 very rapidly increasing, separated by a narrow, well-impressed sut- 

 ure ; last whorl large, sloping above, impressed in the middle, all 

 over obscurely malleated, slightly descending at the aperture, 

 dilated, rounded-angular at periphery, planulate beneath, rounded 



