22 BULLETIN NO. 2. 



middle of the valve and thence rounding into the ventral border. 



Surface of the valve ornamented with 35 to 40 slightly convex 

 radiating cost?e which increase in size towards the free borders of 

 the shell. 



Eight valve nearly flat, ears rather more prominent than on 

 the opposite valve, and radiating costae less distinct. Length 

 from the beak to the ventral margin | mch ; greatest breadth Yw 

 inch ; length of hinge Hne f inch. 



Named in honor of Prof. John CoUett, the able State Geologist 

 of Indiana. 



Position and locality : From the shaly beds of the Keokuk 

 group, Crawfordsville, Indiana. 



No. '2512 of the Illinois State collection. 



Collector, Frank H. Bradley. 



AVICULOPECTEN EDWARDSI. (sp. nOV.) 



Shell of medium size, obliquely ovate, right valve very convex, 

 breadth a little more than the length ; anterior ear rather large, 

 triangular, posterior ear not preserved ; posterior border oblique, 

 and extending in a nearly straight line from the beak to the basal 

 margin ; anterior border moderately rounded from the ear to the 

 basal margin. 



Surface of the valve ornamented with ten or twelve rather sharp 

 prominent costse, with two or three indistinct ones in the inter- 

 vening spaces on the lower portion of the shell. 



Length from beak to base l^^ inches; greatest breadth ij% 

 inches ; length of anterior ear /v inch. 



Position and locality: From the upper division of the Keokuk 

 limestone, Warsaw, 111. 



No. 2511 of the Illinois State collection. 



Collector, A. H. Worthen. 



GENUS LIMA, Bruguiere. 



LIMA? MENARDI. (sp. UOV.) 



Shell small, thin, obliquely ovate, very inequilateral ; ears small, 

 nearly equal in size, triangular ; hinge line straight, and about 

 half as long as the greatest width of the shell. Right valve nearly 

 flat, anterior side projecting forward, with a nearly straight mar- 

 gin to the regular curve of the basal margin ; posterior side shorter 

 than the anterior, and rounding up from the basal margin nearly 

 to the ear, where it makes a slight backward curve, forming a 

 slight sinus just below the ear. 



Surface marked by numerous transverse stria-, that extend from 

 the hinge line quite around the borders of the shell, covering 

 apparently its entire surface. Left valve unknown. 



Length from the hinge line to the basal margin, \ inch ; great- 

 est breadth about the same ; length of the hinge line | inch. 



