1S70.] -^'^'^ [Winehell. 



specimen, which may be a dorsal valve distorted by pressure exerted at 

 the hinge extremities. If undistorted, it belongs, evidently, to a distinct 

 species. 



In many of the Sciotoville specimens, the flssnred tube and other de- 

 tails of the internal structure of the genus are distinctly shown, but there 

 is difficulty in isolating the specimens from the mass. 



A specimen in Prof. Andrews' collection from Newark, which has the 

 beak of the ventral valve somewhat less elevated than usual, and the area 

 considerably vaulted, presents on the cast of this valve generic (?; char- 

 acters which have not before been noticed. The whole width of the broad 

 sinus, in the middle of the valve, is occupied by a pair of very peculiar 

 occlusor scars, separated by the shallow impression of a low median ridge. 

 Each scar appears somewhat like the representation of the head of a sheaf 

 of wheat — the divergent and pendent heads of grain being turned toward 

 the extremities of the shell. The two scars together are an inch broad, 

 and of equal length. These characters recur in a specimen from Shafer's, 

 Pennsylvania. 



I have some suspicion that Syringothyris typa is identical with Spirifera 

 capax, Hall. The principal distinction, so far as I observe, consists in 

 the lobular, anterior prolongation of the ventral sinus of the former. In 

 a specimen having a transverse diameter of 3i inches, and a height of 

 area of If inches, the ventral sinus projects three-fourths of an inch be- 

 yond the general front of the shell. All of my specimens present this char- 

 acter ; but it does not appear in the description and figures of 8. capax. 

 As this is a character which probably bears a relation to the age of the 

 shell, it may be that 8. capax was described from immature specimens. 

 If so, this species should be known as Syringothyris capax. 



Spikigeka Hannibalensis, Swallow (St. Louis Trans, vol. I, p. 649). 

 Several good casts from bed No. 4, Sciotoville, some of which show both 

 valves. Impressions of the exterior are common, showing that this spe- 

 cies flourished to luxuriant dimensions. A pair of spines is preserved, 

 with a bit of smooth shell attached. 



Spieigera Ohieksis, Win. (Proc. A. Nat. Sci., Phil., July, 18()5, p. 

 118.) From bed No. 4, Sciotoville, Ohio. 



Rhynchojsella Sageriaka, A¥in. (Proc. Acad. N. Sci., Phil., Sept., 

 1802, p. 407.) Six specimens from dark bituminous shales, Tennessee. 

 Also, from Newark, Ohio ; bed No. 4, Sciotoville ; Granville (abundant, ) 

 and from " Cincinnati Furnace," Vinton county, where it is of frequent 

 occurrence. 



This is a common and widely distributed species. I have heretofore 

 known it from remote parts of Michigan, and from Medina, Ashland, 

 Cuyahoga, Summit and Licking counties, Ohio. 



Rhynchonella Missoxjrieksis, Shum. (Mo. Report II, 204.) From 

 bed No. 4, Sciotoville, Ohio. 



Rhynchonella Marshalleksis, Win. (Proc. A. N. S., Phil., Sept., 

 1862.) From Granville, Licking county, Ohio. 



A. P. s. — VOL. XII — B. 



