Limestone Fossils. 193 



The peculiar " worm-eaten '' appearance of the irregular pitting 

 of the surface is equally marked in the two specimens before me. 



Rare in the carboniferous limestone of Lowick. 



{Col. University of Cambridge.) 



Macrochilus linnmformis (M'Coy). 



Desc. Elongate fusiform, very acutely rhomboidal, greatest 

 width at about the middle of the total length, from whence 

 the anterior or basal part is conoidally attenuated or rapidly 

 sloped to the greatly narrowed front of columella, and very 

 rapidly sloped to the suture, which is simple and slightly im- 

 bricating ; spire very abruptly attenuated, long, very slender ; 

 sides verj- concave in the profile of about six or seven whorls 

 (usually five preserved) ; apical angle 54°; surface polished 

 very smooth, with occasionally fine traces of obsolete direct 

 lines of growth; mouth narrow, elongate, contracted before 

 and behind ; anterior part of columella very slightly thickened. 

 Length about 1 inch 7 lines, proportional length of mouth of 

 body-whorl y^^, width of body-whorl y^^'^, width of penul- 

 timate whorl j^Q, space between last and penultimate sutures 

 ■^jj, width of mouth ■^^■^. 



This beautiful species is so totally distinct in foim from any of 

 those described that it is unnecessaiy to compare them. The 

 very abrupt attenuation of the elongate spire gives so much the 

 outline commonly seen in Linnaa as to suggest the specific 

 name : in addition to this remarkable peculiarity, the species 

 difl'ers from its congeners in the conoidal attenuation of the pro- 

 duced front, from the line of greatest width of body-whorl, which 

 is at about one-third its length below the suture. 



Not very uncommon in the carboniferous limestone of Lowick, 

 Northumberland. 



{Col. University of Cambridge.) 



Macrochilus brevispiratus (M'Coy). 



Desc. Elliptical, moderately gibbous, most so about the middle of 

 the length; spire about one-fourth of the total length, pointed; 

 of four whorls gently convex in the middle; sutures slightly 

 imbricating; apical angle varying from 82° to 100°; anterior 

 portion or base produced, moderately convex ; surface smooth, 

 with vei-)- faint tine strife of growth visible near the mouth, 

 being scarcely sinuous and veiy slightly oblique ; mouth elon- 

 gate ovate, indented by the posterior part of the body-whorl ; 

 anterior half of columella thickened, arched. Length of rather 

 small specimen 9 lines, proportional length of mouth or last 



