422 PROCEEDINGS OF THE ACADEMY OP 



Locality. Gaines, Kent county, from large angular fragments of a purplish.- 

 red, friable sandstone, strewn along the region of outcrop of the Marshall 

 sandstone throughout the western part of the State. 



Sanguinolaria sectoralis, n. sp. Shell rather large, subtumid, triangular, 

 with beaks but little in advance of the middle. Anterior and posterior car- 

 dinal slopes but slightly curved, the latter the longest ; anterior end a broad 

 curve ; posterior more produced and more abruptly curved between the ex- 

 tremities. Beak prominent, somewhat depressed, incurved. Greatest thick- 

 ness of shell in the middle. Muscular pits situated above the middle, oval, 

 profound, connected by the entire pallial impression. 



Length 1-18 (100) ; height -92 (78) ; thickness -54 (45) ; length of anterior 

 end -43 (36) ; of posterior end # 75(63). Length, height and thickness of 

 largest specimen seen are 1-75 (100), 1-30 (74) and -70 (40) ; length of ante- 

 rior end *80 (45) ; of posterior end - 94 (53). 



Loca lity . Marshall . 



Solen, Linnaeus. 



Solen scalpriformis, n. sp. Shell of moderate size, having the hinge line 

 straight, and the ventral regularly curved, and so situated that its chord forms 

 posteriorly, an angle of about 5 with the dorsal margin ; extremities abruptly 

 rounded the anterior one regularly, the posterior truncately. Valves with 

 a slight constriction beneath the subterminal beaks, which corresponds to a 

 strong ridge within, fading away at about half the distance from the dorsal to 

 the ventral margin. Valves but moderately inflated, flatter behind, and a 

 little drawn together anteriorly. Exterior surface marked by incremental lines 

 nearly concentric with the pallial border. 



Length of shell 2*05 (100) ; projection of anterior extremity beyond the 

 beaks -11 (5) ; greatest width of shell (one-third its length from forward end) 

 56 (27) : width at two-thirds the shell-length from forward end *48 (23), 

 whence it narrows rapidly. 



Localities. Marshall and Moscow, abundantly. Also, near Napoleon. 



A well marked variation in form has been observed in many specime ns, 

 having a straight ventral border and more uniform width. 



Solen quadrangularis, n. sp. Shell of medium size, quadrangular; hinge 

 margin straight, somewhat shorter than the ventral margin, which is also 

 straight through the greater part of its length, but is abruptly rounded up- 

 wards anteriorly, and a little more gradually rounded posteriorly. Beaks 

 terminal ; anterior extremity of shell transversely truncate, posterior obliquely 

 so. Valves rather tumid anteriorly, becoming less so posteriorly ; not at all 

 contracted toward the gaping extremities. A constriction appears close to the 

 anterior extremity, which corresponds to a ridge within, narrow and sharp 

 near the beak, but becoming broad and depressed towards the opposite mar- 

 gin. Surface marked by distinct lines of growth running parallel with the 

 ventral and posterior margins. 



Greatest length 2-0 (100) ; width '66 (33) ; posterior truncation forming 

 with hinge-line an angle of about 64. 



Locality. Marshall. 



Solen priscus, n. sp. Shell of medium size, slightly arcuate by an inflec- 

 tion of the two extremities toward the ventral side ; dorsal and ventral mar- 

 gins nearly parallel ; valves but little inflated, giving an oval-lanceolate trans- 

 verse section ; anterior extremity widely gaping, projecting a little beyond 

 the beak, regularly rounded to the ventral side below, and above truncated 

 obliquely backwards to the vicinity of the hinge ; posterior extremity obliquely 

 truncate, with the lower angle abruptly rounded. The cast shows the im- 

 pression of a broad ridge passing from the hinge toward the ventral margin, 

 and is further marked by distinct incremental lines parallel with the pallial 

 border except on the anterior truncation, by which they are intercepted. 



[Sept. 



