230 Monograph of the LamelUhranchiafa. 



general surfoce of the valves depressed convex. Hinge plate strongly 

 arcuate, more abruptly curving in the middle, occupied by ten or 

 twelve teeth on each side of the center, those in the middle being 

 nearly straight, becoming more and more bent and angular toward the 

 extremities ; muscular impressions large and distinct ; pallial line 

 strongly marked, situated considerably within tlie border of the valve. 

 Surface characters of the valves not observed. 



Tellinomya Hllli — (S. A. Miller). 



Fig. '20. Tellinomya Ililli. Internal part of a valve slightly magnified. 



Shell somewhat oval in outline, the posterior end prolonged, with 

 the cardinal border nearly straight, until it bends somewhat circularly to 

 the point of greatest extension ; anterior end quite regularly rounded ; 

 basal margin forming a semi-elliptic curve; beaks near the anterior 

 end moderately p-omuient, greatest convexity immediately behind the 

 beaks; surface smooth. Hinge line occupied by three small teeth 

 anterior to the beak and ten small teeth posterior to it. Some diffi- 

 culty has been experienced in determining the number of teeth from 

 their indistinct character in the specimen examined, and it may be 

 that there are actually more than we have stated. Muscular impres- 

 sions and pallial line not observed. 



The very slight curvature of the hinge line and the minute character 

 of the teeth, as well as their straight transverse character, may leave 

 some doubt as to whether or not this shell belongs to the genus TelU- 

 noniya. 



The specific name is given in honor of Dr. H. H. Hill, of Cincin- 

 nati, who has been an active collector in various departments of natural 

 history for a number of years, and very prominent in the organization 

 and management, from the beginning, of the Cincinnati Society of 

 Natural History. His private cabinet sparkles with mineral gems, is 

 ornamented with the rarest and finest specimens of the workmanship 

 of the Indians and the Mound Builders, and bears upon its shelves 

 many of the choicest fossils from the Cincinnati Group. 



I found this species in the upper 50 feet of the Cincinnati Group, 

 about three miles south of Osgood, Indiana, and nearly fifty miles 

 west of Cincinnati. The valves were found quite abundant, though 

 not well preserved, on slabs, associated with Beyrichia striato-marginatns. 

 An entire specimen was not found. 



