PROSOBRANCHIATA. 229 



much roughened by the lines of growth, giving a scabrous aspect to the shell : the 

 body- whorl is attenuated very gradually in front, assuming a nearly conical shape, and 

 terminates in a long, rather wide, and nearly straight canal. The aperture is lanceo- 

 late, the outer lip moderately arched, and the sinus, which is placed in the margin 

 immediately behind the shoulder, is wide, moderately deep, and almost semicircular 

 in form. 



No foreign analogue of this well-marked species has as yet been noticed; and 

 at present P. fusiformis appears to be confined to the older eocene strata in the 

 neighbourhood of London, where it is exceedingly rare. Mr. Sowerby, it is true, has 

 applied the name to a Pleurotoma from the so-called transition beds between the lower 

 tertiaries and the upper cretaceous formation at Gosau, a notice of which is con- 

 tained in a memoir ' On the Structure of the Eastern Alps,' by Prof. Sedgwick and 

 Sir Roderick Murchison, published in the 'Geological Transactions' of 1831; but 

 that shell is a short, wide, strongly costated shell, perfectly distinct in character from 

 the Highgate shell, and the name fusiformis was used apparently in forgetfulness of its 

 having been previously applied to the present species. The Gosau shell has been 

 since distinguished by D'Orbigny as P. sub-fusiformis. 



The specimens figured form part of Mr. Wetherell's collection. 



Size. — If the larger specimen were perfect, the dimensions would be — axis, 1 inch 

 and 9-12ths ; diameter, 6-1 2th s of an inch. Those of the specimen figured in ' Mineral 

 Conchology' appear to be — axis, 2 inches and l-12th; diameter, rather more than 

 7-12ths of an inch. 



Locality. — Highgate. 



No. 154. Pleurotoma sulculosa. F. E. Edwards. Tab. XXVII, fig. 2 a — c. 



P. testa elongatd, fusiformi, sub-turritd, concentrice sulcata : anfractibus convexiusculis, 

 angulatis, lubcrcidatis ; marginibus posticis pauxillulum cavatis, transversim interrupte 

 lineal is, ad sutaram incrassatis : aperturd oblongo-ovali, in canali longiusculo exeunti ; 

 labro valde arcuato ; sinu lato, sub-trigono, in margine collocato. 



Far. /3. Testa tuberculis longitudinaliter compressis, ultimo anfractu evanescentibus, 

 instructd. 



Shell elongated, fusiform, transversely sulcated ; spire formed of seven or eight 

 volutions, moderately elevated, pointed : whorls rather convex, angulated at the 

 shoulders, where they present a series of oblong, longitudinally compressed, and more 

 or less oblique tubercles ; the posterior margins slightly hollowed out, thickened on 

 the sutural edge, round which runs an elevated, sharp line, granulated by the lines of 

 growth of the sinus ; the space between this line and the angle of the whorls is occu- 



30 



