194 Twenty- FOURTH Report on the State Museuii. 



ventricose, with two distant carinas having a wide, vertical, slightly- 

 concave space between, which occupies more than one-third the height 

 of the volution. Upper side of the volutions convex for half the dis- 

 tance to the carina, and below this they are concave, giving the form 

 of an ogee. 



In another specimen, apparently identical, the upper side of the 

 volutions are slightly concave and regularly sloping downward from 

 the suture to the carina. Lower side of the volution not carinate ; 

 umbilicus small, or closed with a callosity. 



Surface marked by fine strise of growth, which are turned back- 

 ward from the suture, and are vertical on the sides of the volution, 

 and on the lower side curve backward to the umbilical area. 



Formation and locality. In the upper limestones at the Falls of 

 the Ohio. Cabinet of Dr. James Knapp and other collections. 



Trochonema Yandellana 01. sp. 



Shell turbinate, volutions about five (three of which are preserved 

 in the specimen), rapidly increasing, carinated ; the last volution 

 becoming ventricose and marked by seven revolving caringe, includ- 

 ing the one bordering the somewhat channeled suture ; four of the 

 carinae are distinctly marked by thin lanceolate nodes, which become 

 more prominent with the increased growth of the shell, while the 

 other three, — one bordering the suture and two on the lower middle 

 portion of the volution, — are destitute of nodes (in the specimen 

 described), but may possibly assume this character in more advanced 

 stages of growth. The carinas are situated, one at the suture and one 

 bordering the moderately large umbilicus, with five on the body of 

 the volution, of which two are above the middle and three below ; 

 the spaces separating those bordering the suture and umbilicus from 

 those on the body of the volution, are considerably wider than the 

 spaces between the intermediate carinae. Aperture rounded, sliglitly 

 modified by the carinse. 



Surface marked by fine transverse striaB of growth, which turn 

 backward as they cross the volution, to the umbilicus. 



This species has the general form and proportions of T. uiiibilicuta 

 Hall, from the Trenton limestone, and also of T. tricarinata Meek, 

 from the Upper Helderberg limestones, but difiers from both in the 

 greater number of carinse and in their nodose character. 



Formation and locality. In the " Hydraulic beds," near Louis- 

 ville, Ky. Cabinet of Dr. James Knapp. 



