﻿PROSOBRANCHIATA. 



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form in the animal, and is not due, as in P. turbida, to the successive terminations 

 of the sinus, which in the French shells is placed in the margin of the whorl, and not 

 on the shoulder, as in this species. These two shells, therefore, cannot, with pro- 

 priety, be referred to the same species ; and D'Orbigny has in fact distinguished the 

 French shells by the specific name pseudo-colon. 



The shells from Basele, Boom, Schelle, and Antwerp, referred in the first 

 instance by Nyst, and afterwards by De Koninck, to P. colon, are also specifically 

 distinct, and have been subsequently separated by Nyst, under the name of P. crenata. 



There still remain to be noticed certain shells from Vliermael and Lethen ; these, 

 in the first instance, were also referred by Nyst to P. colon ; but that author, in his 

 description of the fossils of Belgium, has erroneously considered P. colon of Sowerby 

 as specifically distinct from P. turbida of Solander, and has treated the shells in 

 question as belonging to P. turbida. I have not seen any specimens of the Vliermael 

 and Lethen shells ; but, judging from the specimen figured in Nyst's work, apparently 

 a full-grown shell, I do not consider that it has been correctly referred to the present 

 species ; the spire is shorter and more conical, the whorls are more convex, the 

 posterior margins wider and less depressed, and the sutural edges not thickened nor 

 girt by the prominent, raised lines found in the present species ; the tubercles on 

 the shoulder are much less prominent, the body whorl is contracted in front into 

 a narrow, somewhat lengthened, canal, the outer lip is not so much curved, and 

 the sinus is apparently triangular and much wider and shallower. 



Size. — Axis, 1 inch and 11-1 2ths ; diameter, rather more than 7-12ths of an inch. 



Localities. — Barton and Highcliff, at both of which places it is very common. In 

 Morris's catalogue, Highgate is also given as a locality for P. colon ; but I am not 

 aware of the present species having been found there. 



No. 238. Pleurotoma ligata. F. E. Edwards. Tab. XXXII, fig. \2 a, b. 



P. testa scabrd, elongato-turbinatd, suh-fusiformi, concentrice fasciolis crassis, quasi 

 funiculis, ligata : anfractibus convexiusculis, ad limner os curvi-crenatis ; marginibus posticis 

 latis, transversim tenuiter lineatis, et sulco pro/undo exaratis, ad suturam incrassatis, longi- 

 tudinaliter crasse plicatis ; ultimo anfracfu conoideo, in canalem latum, brevem, ad basin 

 paululo emarginatum, producto ; fasciolis concentricis crassis, praeminentibus, sub-distan- 

 tibus, rotundatis, interstitiis sub-planis : aperturd oblongo-ovali ; labro valde arcuato, acuto : 

 sinu latiuscuto, prof undo, marginibus parallelis, ad humerum coltocato ; columella contortd 

 sub-callosd, antice cristatd. 



Shell rugged, elongated, fusiform, and ornamented with thick, rounded bands, as if 

 bound with cords ; the spire, formed of eight or nine volutions, is nearly conical, and 

 moderately elevated, being as long as the aperture. The whorls present round the 



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