]!)0 TEST AVE A ATLANTIC A. 



In its olit i isc, cupola- or dome-shaped upper portion, and its 

 downwardly-produced tectiform keel, as well as in its ultimate 

 volution having no tendency to be deflected at the aperture, the 

 present shell has very much in common with the H. Bulwerii. 

 Nevertheless it is (on the average) a trifle smaller than that 

 species, its roof-like keel is broader and even still more ex- 

 pressed, its umbilicus is a little more sudderdy and perpendicu- 

 larly scooped-out, its granulations (particularly beneath) are, 

 although extremely variable, very much coarser, and its colour 

 is altogether different,— it being either of a bleached calcareous 

 white, or else (though much more rarely) more or less suffused 

 with a pale livid brown. Its granulations, although so incon- 

 stant as regards their size and development, have a curious ten- 

 dency (at any rate at the base) to be split-up, each of them, 

 into several compartments, by minute intersecting lines, — so 

 that in examples where they are largely expressed and elongated, 

 each one has somewhat the appearance of a bundle, or fascicle, 

 of smaller ones placed side by side (like the closed-up club of a 

 Coleopterous Lamellicorn antenna). 



The ' var. oV of the present enumeration, which was enun- 

 ciated by Dr. Albers, under the name of H. Ludovici, as 

 specifically distinct, is merely a rather larger and more flattened 

 (or lenticular) phasis of the shell, with generally a more open 

 umbilicus, which appears (so far at least as I have been able to 

 ascertain) to have died out; for although it possesses several 

 small features of its own which will suffice usually to separate 

 it at first sight from the ordinary type, it nevertheless merges 

 so gradually and completely into the latter that I am satisfied 

 it cannot be upheld as more than a modification, or race, which 

 may formerly perhaps have represented the normal aspect of 

 the species. In its most exaggerated state (under which cir- 

 cumstances it measures about 9 lines across its broadest part) it 

 is not only somewhat larger and more depressed than the one 

 which is now so abundant, but it has its keel a trifle less roof- 

 like or pronounced, and its basal region appreciably more 

 inflated or convex. The volutions, too, of its somewhat less 

 cupola-shaped spire are not quite so decidedly flattened, having 

 a tendency to be a little gibbose or convex behind the suture ; 

 but many of the examples now before me possess these various 

 characters so doubtfully that it is impossible to decide whether 

 they pertain to the ' 8. Ludovici ' or not. 



(§ Crasjpedaria, Lowe.) 



Helix delphinula. 



'Delphinula sulcata, Lam. ?' Bowdiclu Exc. in Mad. 140. 



f. 33. a, b. (1825) 



