248 PALEONTOLOGY OF NEW JEESEY. 



Unio humeroBoides. 

 Plate XXXI, Fig. 4. 



Unio humerosoides Lea. Proc. A. N. Sci. Phil., 1868, p. 163. Pamphlet by Lea, p. 131. 



'* Shell smooth, ovately oblong, very much compressed, rounded be- 

 hind and before ; beaks slightly raised, removed from medial ; cardinarteeth 

 large and compressed; lateral teeth rather long and slightly curved. 

 Length 2.6, breadth 4.2 inches." (Lea.) 



The shell marked as the type of this species in Mr. Lea's collection 

 in the Academy is of a broad oval form, being longer than high, as indi- 

 cated by his measurements. It resembles so closely those referred to U. radi- 

 atotdes as -to be not easily distinguished in the imperfect condition in which 

 they are found. On close examination it will be seen not to round forward 

 so rapidly on the posterio-cardinal border as does that species, and to be 

 somewhat proportionally broader from the base to the cardinal line. The 

 surface of the type specimen shows evidence of having been rather coarsely 

 marked with concentric undulations on the posterior part. The specimen 

 figured is Lea's type. 



Unio Roanokoides. 



Plate XXXIII, Figs. 1 and 2, and Plate XXXIV, Fig. 7. 



TJnio Boanokoides Lea. Proc. A. N. Sci., Phil., 1868, p. 164. Pamphlet by Lea, p. 31. 



Shell transverse, subquadrangular, nearly twice as long as high ; arcu- 

 ate on the hinge-line in the cast, and broadly rounded on the base. Ante- 

 rior end rather sharply rounded ; posterior end truncate and a very little 

 oblique ; longest below. Beaks situated at about the anterior third of the 

 length. Valves compressed, more particularly so on the anterior side of the 

 beaks. The teeth have been strong ; the cardinals wide but not strongly 

 elevated ; the laterals long, slightly curved, and quite thickened in some 

 cases toward the outward end. Muscular scars large, well marked, and 

 circular. 



This species closely resembles Z7. humerosoides in its general outlines, 

 but is somewhat longer from anterior to posterior, and the latter extremity 

 is possibly a little more strongly truncate. The separation is, however, 

 merely arbitrary. Among older forms of fossil shells I should not think of 



