;i04 Xiuc Sjiecics of Fusi<iisfroi/i O/iio. 



sufficient reason among the species referred to C'oleoltis by its 

 author, for a generic separation from Dentalinm, other than 

 their more strictly straight foi'm. But there are straight or 

 nearly straight Dentalia, and also curved forms which he has 

 referred to the new genus. The generic feature "shells thick"" 

 Avould also be opposed to i)teroi)odons affinities. In its more 

 rapid taper and greater curvature, it is sufficiently distinct from 

 described forms of that genus. 



Fonn(Ui())i and Loadif//.— In the cherty layers of the Uppei' 

 Helderberg limestones, near Dublin, Ohio. 



9Iacroclieilus priscus, u. sp. 



Pal. O., Vol. Ill, Plate 3, Figs. 3 and 4. 



Shell small and very ventricoye, the height but little greater than the di- 

 ameter of the body volution ; the former in the tigured example being three- 

 eighths of an inch, and the latter only about one-sixteenth of an inch less. 

 Shell composed of about four volutions, which are very veutricose and rapidly 

 increase in diameter, the last one forming the great bulk of the shell, being 

 fully two-thirds of the entire height. Suture-line distinct, but not strongly 

 marked. Apical angle about eighty degrees. Aperture somewhat semilu- 

 nate, strongly modified on the inner side by the body of the preceding volu- 

 tion, which occupies fully one half its height. Columella strong, straight 

 and rounded, and the twisted ridge obsolete. Surface of the shell appa- 

 rently smooth ; at least no striai are perceptible. 



This pretty little species reminds one strongly of J/, veniri- 

 casus, Hall, from the Coal-measures, but is somewhat shorter in 

 the spire, although resembling it in most other respects. The 

 substance of the shell is soft and chalky, and might not I'etain 

 minute surface striae if they had ever existed ; but no remains 

 of them are visible at present. 



Furmatio)) ((iid Locality. — In the white (dierty layers of the 

 Upper Helderberg group, near Dublin, Ohio. 



Losionema parvuluni, u. sp. 



Pal. O., Vol. Ill, Plate 8, Fig. 5. 



Shell minute, scarcely exceeding a fourth of an mch in length, and pro- 

 portionally slender, with a rapidly ascending spire, which is slightly more 

 rapidly tapering in the upper than in the lower part. Volutions six or six 

 and a half, moderately convex on the outer surface, and more strongly 

 rounded on the lower part of the exposed portion than on the upper ; 



