194 Prof. F. M'Coy on some new Carboniferous 



whorl -^^^, width of body-whorl -^■^■^, width of mouth y^^, 

 space between last and penultimate sutures yy^Q. 



The extreme shortness of the spire separates this form from 

 all of the genus at once_, except the M. Michotianus (D^Kon.) ; 

 from that globose species, it is distinguished by its much more 

 elongate slender form (indicated by the much less proportional 

 width of the body-whorl when compared with the total length), 

 fewer spiral whorls, less convexity, and the whorls sloping gra- 

 dually to the sutures. 



Rare both in the lower carboniferous limestone of Derbyshire, 

 and in the carboniferous limestone of Lowick, Northumberland. 



{Col. University of Cambridge.) 



Straparollus costellatus (M'Coy). 



Desc. Discoidal, depressed, very obtusely conic ; spire of rather 

 more than six very gradually increasing whorls, each slightly 

 convex above, strongly indenting the suture, which is an im- 

 pressed sharp line ; apical angle 110° (from the obtuseness of 

 the apex its angles would be larger in veiy young specimens) ; 

 umbilicus very wide, rounded, half exposing all the whorls ; 

 base of body- whorl very convex, rounded, with a very obscure 

 angulation at the edge of the umbilicus ; periphery narrowed, 

 obtusely rounded ; upper surface of the whorls marked with 

 sharp, slightly sigmoid, rather unequal ridges, arched ob- 

 liquely backwards, becoming abruptly very much finer and 

 more numerous on passing the circumference to the base (ten 

 of the upper ridges in two lines on the body- whorl), each 

 separated by a sulcus about its own width from the next. 

 Diameter 1(3 lines, proportional height of spire -^^q, height of 

 last whorl y^^jj, distance between last and penultimate suture 

 tVo' width of umbilicus ■{—, width of mouth ■^■^■q. 



This species is distinguished from its congeners by the beau- 

 tifully sharp costellation, or transverse sculpturing of the whorls 

 of the spire, which abruptly cease on the base of the body-whorl, 

 or become there confounded with the lines of growth. The 

 inner lip is complete, but thin, as in other species of Straparollus, 

 distinguishing them from Platyschisma. 



Rare in the lower carboniferous limestone of Lowick, North- 

 umberland. 



{Col. University of Cambridge.) 



Nautilus ? costato-coronatus (M^Coy). 



I give this provisional name to a fragment too imperfect to 

 allow of full description, but so strongly marked, and unlike all 



