28 SYNOPSIS OF THE CHARACTERS OF THE 



Mackocheilus. PliiL 



This name has been proposed by Professor Phillips for those shells of the carboniferous limestone pre- 

 viously called Buccinum. To that genus of course they do not belong, as their base is not notched. Such 

 species as the M. sigmilinem, M. elongatus, &c., seem referrible to the recent genus Chrysodomus, of which 

 the Fusus antiquus of our coasts is the type ; and including those bucciniform shells, which have the base pro- 

 duced into a channel shorter than the spire ; the whorls ventricose ; the outer lip thin, and the inner lip obso- 

 lete ; those fossils were, therefore, most probably carnivorous, like the Fusukb just mentioned, although the 

 aperture is entire. 



Mackocheilus acutus. Sow. sp. 



Buccinum acutum. Sow. Min. Con. — Buccinum acutum. Phil. GeoL York. (?) 



Sp. Ch. — Acutely conical, smooth; volutions numerous; spire longer than the aperture. 



This is a very elegant species ; the spire is composed of five or six convex whorls, the body whorl small 

 and contracted at the base, surface smooth. Length one inch eight lines. Diameter of body whorl nine 

 lines. 



Mackocheilus canaliculatus. M'Coy. (PL V. fig. I . 



Sp. Ch. — Ovate; spire acute, turricidated, composed of five flat whorls, channeled at the sutures ; body 

 whorl as long as the spire, convex ; surface smooth. 



This pretty species is remarkable for the flatness of the whorls of the spire, and the channeled sutures. 

 Length five lines, width of basal whorl three lines. 



Mackocheilus curvilineus. Phil. sp. 



Buccinum curvilineum. Phil. GeoL York. 



Sp. Ch. — Very elongate ; volutions broad, slightly convex, obscurely striated ; spire twice the length of the 

 aperture. 



This species has the body whorl very little larger than that which precedes it ; the spire is very long, 

 although of comparatively few turns, the width of each volution equalling the diameter of the shell at that part ; 

 the transverse stria; on the volutions are very oblique, and somewhat curved, whence the name. Length one 

 inch five lines ; diameter seven lines. 



Mackocheilus imbkicatus. Sow. sp. 



Buccinum imbricatum. Sore. Min. Con. — Buccinum imbricatum. Phil. Geol. York. 



Sp. Ch. — Ovate ; spire shorter than the aperture ; volutions convex, with very fine, transverse strise. 

 Very nearly related to the M. acutus, but less elongate, and having the body whorl larger in proportion to 

 the spire. Length one inch seven lines ; diameter of body whorl ten lines. 



Mackocheilus fimbrlatus. M^Coy. (PL V. fig. 2). 



Sp. Ch. — Ovate, ventricose ; spire equal in length to the last volution, of three or four rounded whorls ; all 

 the sutures strongly fringed or crenated ; whorls crossed by fine, sigmoidal striae. 



This minute species has the sutures very strongly crenated. Length one line; width half a line. 



