374 Mr, Broderip and Mr. G. B. Sowerby on some 



Turbo, Buccinum and Cancellaria. From Turbo it may easily be known 

 by its thin shell, its elliptical and not spiral operculum, and by the 

 absence of the ciliated lateral membranes which belong to the Turbines. 

 From Buccinum, it is distinguished not only by the discrepancies ob- 

 servable in the soft parts, but also by the general habit of the shell, and 

 more particularly by the want of a notch at the base of the aperture, and 

 by the very indistinct canal. From Cancellaria it may be at once known 

 by its being destitute of the oblique folds near the base of the columella : 

 — it appears, however, to be the type connecting the true Buccina 

 f Buccinum undatum and its congeners) with the Cancellarise. 



We have trespassed thus far on the patience of our readers, that they 

 might have before them our reasons for constituting a new genus. They 

 appear to us to be peremptory, otherwise we should have abstained from 

 adding to the list of genera. 



The specimens are not sufficiently well preserved to enable us to exa- 

 mine or describe the internal structure. 



Trichotropis bicarinata. 

 Tab. IX. fig. 4—8. 



T. testd anfractihus, quinque, ultimo ventricoso, carinis duabus vali- 

 dis ; long. l:y%, poll., lat. I^Vj /'o//. 



Syn. Turbo bicarinatus, Sowerby in Tank. Catal. App. p. xii. 

 Hob. in Oceano Arctico. 



Shell with four or five volutions, the last of which is much larger than 

 the others, and ventricose, — smooth on the outside, with two prominent 

 keels, which are ornamented with the numerous strong, sharp-pointed, 

 bristle-like processes formed by the epidermis. The aperture is large, 

 and rather triangular ; being, however, rounded externally, with two obtuse 

 angles, and pointed at the base. The shell has a very narrow, linear 

 umbilicus, which is carinated on the outer edge, and its carina is bristly 

 like those on the back ; its inner edge is formed by the elevation of the 

 edge of the inner lip. The columella is rather flattened. Shell white, 

 translucent, epidermis pale horn colour. 



Near the apex of the shell which wras in the Tankerville collection, 

 and which is now in the museum of Dr. Goodall, two Terebratulse 



