42 MOLLUSCA FROM THE CRAG. 



commerce by the name of Figs as the type of his genus Pyrula. Mr. G. B. Sowerby, 

 in his Genera of Recent and Fossil Shells, had also previously excluded all others 

 from this genus, for which he retained the name of Pyrula; and although the 

 dissimilar shells still united with these must hereafter be separated, the name of 

 Pyrula ought to be retained for this section. The recent species of this genus, or 

 section, are found only within the tropics. 



1. Pyrula reticulata. Lam. Tab. IT, fig. 12. 



Bulla ficus, var. 1. Broc. Conch, foss. Subap. p. 279, 1814. 



Pyrula reticulata. Dvjai-d. Mem. de la Soc. Geol. de France, Ency. Meth. pi. 432, fig. 2. 



— Lam. An. sans Vert. 2d edit. t. ix, p. 510. 



— S. Wood. Catalogue, An. and Mag. Nat. Hist. 1842, p, 543, pi. 5, fig. 17. 



— G. Sowerby. Genera of Shells, fig. 1. 



— Phil. En. Moll. Sic. vol. ii, p. 180, 1844. 



P. Testa Jicoided, pyriformi, ventricosd, tenui, cane ell at a ; spird brevisnmd, convexd, 

 retusd ; atifractibus circa quatuor inflat 'is ; aperturd ampld, ovatd ; canali angustata ; labro 

 acuto. 



Shell thin, ventricose, pear or fig-shaped; spire short and convex; volutions 

 about four, cancellated, transverse striae the more elevated ; aperture large, 

 subovate ; with an elongated caudal termination ; outer lip sharp. 



Axis, 3 inches. 



Locality. Cor. Crag, Ramsholt. Recent, Indian Ocean. 



My cabinet contains only two specimens of this shell, which appear to differ in 

 some slight degree from the Oriental species. The upper part of the outer lip is 

 more elevated, the whole shell is not quite so slender, and the transverse ridges are 

 rather broader and flatter. The specimen figured does not represent the canal so 

 elongated as it is in the recent specimens, but a portion of it is broken away ; the 

 lines of growth indicate a similar length. 



If this be Pyrula reticulata of Lamarck, which I presume it is, its retirement or 

 mioration to the southward and eastward might have been through the seas that 

 deposited the Touraine beds, whence, in all probability, it originally came, and 

 had an extension of existence through the more modern (?) deposits of Calabria, 

 in which it is found fossil, as quoted by Philippi. Conceiving a communication to 

 have then existed between the Mediterranean and the Arabian Gulf, a further 

 extension to its present habitat might have taken place through the channel now so 

 effectually closed by the Isthmus of Suez. 



The presence of this species in a latitude so high as that of England has been 

 accounted for upon the supposition that the temperature of the sea by which the 

 Coralline Crag was deposited was more favorable to its existence than the seas of 

 the same latitude are at the present day ; but a very elevated temperature does not 

 appear to have been essential to its existence 9 if we may judge from its associates, 

 Tricotropis borealis, Nuculapyymaa, &c, which are now found only on our own northern 

 coasts, and in the Arctic Seas. The supposition that those northern forms at that 



