910 NEW YORK STATE MUSEUM 



convex; beaks on the anterior third and incurved. An average 

 sized specimen measures 7 mm in length, 4% mm in hight and 

 3 mm in thickness. These pyrite specimens differ from the 

 typical P. p 1 a n a in being somewhat shorter, in which they 

 resemble young forms. 



Localities. Fairly common at all the localities examined : i. e. 

 Canadaigua lake, Livonia, Moscow and Greigsville. Total speci- 

 mens 16. 



Palaeoneilo constricta Conrad, mut. pygmaea nov. 



Plate 1, fig. 12, 13 



This form is subovate in outline, the length being about one 

 half greater than the hight. The beaks are well to the anterior, 

 and the valves moderately convex. Several concentric lines of 

 growth are imprinted on the cast. The main and distinctive 

 feature is a depression which runs from the beak to the rear 

 margin of the shell. 



Localities. Greigsville and Little Beard's creek, Moscow. 

 Total specimens 3. 



Genus paracyclas Hall 

 Paracyclas lirata Conrad, mut. pygmaea nov. 



Plate 1, fig. 2, 3 



This neat little form is almost circular in outline, the anterior 

 margin swelling out strongly, while to the rear the slope from 

 the beak is very rapid. The beaks are centrally situated and 

 directed to the front. They are small and incurved. The sur- 

 faces of the casts are perfectly smooth. A typical specimen 

 measures 1% mm in length, 1 mm in hight and % mm in thick- 

 ness. As compared with the normal P. lirata, it has about 

 one twentieth the diameter, shows no sign of ornamentation, 

 looking like a young form. However, it occurs in great abund- 

 ance presenting a remarkable uniformity of size and appearance. 



Localities. It is the most abundant fossil at Canandaigua lake 

 and the Livonia salt shaft and occurs also, though less abund- 

 ant, at Greigsville. Total specimens 110. 



Genus grammtsia DeVerneuil 

 Grammysia constricta Hall, mut. pygmaea nov. 



Plate 2, fig. 1 , 2 



This little form has the shape of a truncated ovoid, the beak 

 being at the anterior end. The hinge line is straight and two 



