INSTITUTE OF SCIENCE, PHILADELPHIA. 85 



which at all approximates in structure the fossil species, by the ready 

 adaptability to variation which the recent form exhibits. So marked, 

 indeed, is this tendency to vary that some of the extreme varieties of the 

 species might almost be said to approach more nearly 5. Leidyi than 

 their own type forms. This variation is seen in the flattening of the 

 whorls of the spire, the less prominence of the wings, and in a reduction in 

 the size of the tubercles of the body-whorl, characters, in the accentua- 

 tion of which, primarily, -S 1 . Leidyi differs from 5. accipitrimts. In 

 the more common, or what might be called typical, forms of the latter 

 species the wing is quadrangular, exhibiting its greatest expansion above 

 the shoulder-line of the shell ; in the greater number of individuals of 

 S. Leidyi, on the contrary, the wing has a regular crescentic out- 

 line, although a tendency toward quadrangulation is very apparent in 

 many of the specimens. It might be said that the two species vary 

 toward each other in respect of this character, the one showing a 

 tendency toward losing the quadrangulation of the wing, the other toward 

 assuming it. A like variable feature separating the two species is ex- 

 hibited in the nodulation (S. accipitiinus) or non-nodulation (S. Leidyi} 

 of the whorls of the spire. Of much more permanent value as dis- 

 tinguishing characters are the greater elevation and flattening of the 

 spire in 5. Leidyi, the absence of true tubercles on the body-whorl, 

 and the much greater ponderosity of the shell generally. 



Lister figures a stromb (pi. 856), Strombus integer of Swainson, which 

 in many respects, especially in the form and structure of the wing, recalls 

 the Florida fossil. The species is described by Gray in his " Descriptive 

 Catalogue of Shells" (June, 1832, p. 2) as follows: "Shell ventricose, 

 solid, white ; spire elongate, conical ; last whorl nodulose behind ; lip 

 thick, rounded, white." Most authors, it appears, have failed to identify this 

 species, described from a figure alone, as a member of the living fauna, 

 and have accordingly discarded it from their catalogues. Morch, how- 

 ever, claims it as a good species, and adds (Malakozoologische Blatter, 

 xxiv, p. 17) : " In 1869 I obtained by [from] Mr. Landauer, at Frankfurt, 

 a specimen from a French collection marked ' .$". incnnis, Florides,' 

 exactly corresponding to Lister's figure. It is the only [one] I recollect 

 to have seen." His description of the species is as follows : Testa 

 planinsenla, solidula, albcsccns ; spira elongata, acuta, conica ; ultimo 

 anfractu postice leviter nodulose ; labro tcmii cxpanso. Whether or not 

 Morch and Gray refer in their descriptions to the same species, it is a 

 little difficult to determine, despite the assurance given us by the former 

 that his specimen corresponds absolutely with Lister's figures. There can 

 be little question from Lister's drawing that the specimen intended to be 

 represented by him has a thick lip, as correctly interpreted by Gray, 

 whereas Morch maintains that the lip is thin. The general form of 



