PULMONATA. 149 



occur so abundantly in the neighbourhood of London, as well as some from Brackles- 

 ham Bay, although they present points of difference, yet, on the whole, agree so closely 

 with the type that they cannot be regarded otherwise than as local varieties. In the 

 Highgate shells (figs. 1 c, d,) the second row of spines disappears more early than in the 

 Hampshire specimens, and the sutura margin is much thickened ; the columella and 

 the folds upon it, in the younger specimens, resemble those of the type, but, in the 

 mature shell, the columella is more flattened, and additional folds arise among the 

 normal ones, which latter become thicker and more prominent, the whole assuming a 

 callus-like appearance ; the outer lip also is thickened, and the principal spines are not 

 so nodiform. The identity of the Bracklesham Bay shells (figs. 1 e, h,) with the present 

 species is not so obvious ; in them the whorls are wider and more sharply angulated 

 on the shoulder, the ribs are generally more distant, and the spines acute and larger; 

 but among the Highgate shells individuals occur in which the whorls are more sharply 

 angulated, and the spines sharp and projecting. In the thickened sutural margin, the 

 thick, plicated outer lip, the condition of the columella, and the character of the colu- 

 mellar folds, the Bracklesham Bay shells agree with those from Highgate, and I am 

 unwilling, therefore, to consider them to be distinct from the present species. 



Dr. Beyrich {loc. cit.) has described a Volute from Westeregeln, in Magdeburg, 

 which he has named V. devexa, and which he considers to be identical " with a species 

 from Barton not described by Mr. Sowerby;" and, he adds, that " most certainly" his 

 species cannot be the young condition of " V. nodosa, for which the species in question 

 from Barton seems to have been considered." Dr. Beyrich refers to the Highgate 

 Volute, figured in vol. 7, Min. Con. (t. 613, fig. 1), which, he says, "in fact resembles 

 the V. devexa of Barton ;" and also to the Bracklesham Bay Volute figured in Mr. 

 Dixon's work; and this last, he adds, "judging from the figure, is scarcely distinguish- 

 able from the Barton species." One of the prominent characters of the Hampshire 

 shells is the very obtuse angle at which the whorl is bent at the shoulder, giving a sub- 

 conical form to the spire. This character distinguishes the Highgate shells, although, 

 as I have stated, it is less strongly marked in those from Bracklesham Bay ; it is also 

 found in the Westeregeln shells, and is particularly noticed by Dr. Beyrich ; but I know 

 of only one other Volute from the Hampshire beds which possesses it (V. ambigua, Sol.), 

 and this species, even in the costated variety, is perfectly distinct. I am at a loss, therefore, 

 to conceive what the Barton shell is to which Dr. Beyrich refers. His V. devexa agrees 

 so closely with the Highgate form, both in description and figure, that considering, as 

 I do, the Highgate shell to be merely a local variety of the Hampshire V. nodosa, I 

 should have cited V. devexa as identical without hesitation, had not that gentleman 

 expressly stated that it could not be referred to the present species. 



Size. — Axis, 2 inches ; diameter, 1 inch. 



Localities. — Barton, Bracklesham Bay, Highgate, Sheppey. German, Westeregeln 

 in Magdeburg ? (fide Beyr.) 



