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. /usiformis 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 toa 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 /wszformzs 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. swbfusiformis. 
The specimens figured form part of Mr. Wetherell’s collection. 
Size.—lf the larger specimen were perfect, the dimensions would be—axis, 1 inch 
and 9-12ths; diameter, 6-12ths of an inch. Those of the specimen figured in ‘ Mineral 
Conchology’ appear to be—axis, 2 inches and 1-12th; diameter, rather more than 
7-12ths of an inch. 
Locality.—Highgate. 
No. 154. PLeuRotoma sutcutosa. F. £. Edwards. Tab. XXVII, fig. 2 a—e. 
P. testi elongata, fusiformi, sub-turrita, concentrice sulcatd : anfractibus conveaiusculis, 
angulatis, tubcreulatis; marginibus posticis pauaillulum cavatis, transversim interrupte 
lineatis, ad suturam incrassatis: aperturd oblongo-ovali, in canali longiusculo exeuntt ; 
labro valde arcuato ; sinu lato, sub-trigono, in margine collocato. 
Var. B. Testd tuberculis longitudinaliter compressis, ultimo anfractu evanescentibus, 
mmstructd. 
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 
