Rav.moni) : Bracmiopoda and Ostracoda of the Ciiazy. 255 



This species, w hicli was originally clescTil)ccl from the Ottawa X'allcy, 

 is very abundant in the Chazy at various points along Lake Chaniplain. 

 The carapace has no very strongly marked characteristics, and the 

 shell is distinguished i-hiell\ 1)\- its uniforniK small size and regular 

 com e\it>'. 



Description. 



Shell small and kidney-shaped. Hinge line nearly straight and 

 less than the greatest length. Both valves strongly convex, thickest 

 a little back of the middle. The height of the shell is only slightly 

 greater at the back than at the front. Both eye-spot and muscle- 

 spot are very small and fri'qiiently indistinguishable. Both ends are 

 regularly rounded, and the ventral margin is only slightly convex. 



Locality. — Common in the Chazy at Chazy, \'alcour, Valcour Island,, 

 and Crown Point, New York, and in the I.owxille throughout the 

 Ottawa X'alley. 



Genus Eurychilina Ulrich. 

 3. Eurychilina latimarginata Raymond. 



Priniilia lalimarginala Ravmoxu, 1905. .American Journal of Science, series 4, 

 Vol. XX, p. 380. 



Description. 



"Carapace small and depressed. Front and posterior margins 



meet the dorsal margin at angles of little more than 90°. Both ends 



are broadly rounded, the ventral margin is gently curved. The shell 



is a little higher at the posterior end than 



in front. There is a deep sulcus just in 



front of the middle, which starts from the 



dorsal margin and extends half-w^ay down 



the valve, turning a little forward at the 



lower end. On well-preserved specimens, 



in front of this sulcus there is a prominent 



eye-spot, which is sometimes translucent. ^'^' ^^' ^-'^''ychtlina; 



_^f , . , ,. t 1 • lalimarginala Raymond. A 



Often there is another slight depression or . ^ u r .i. u ■ . 



° ' photograph of the holotype. 



sulcus in front of the eye-spot. The border Larger tlian natural size, 

 is wide, concave, and of nearly uniform 



width all around from the anterior angle of the dorsal margin to the 

 posterior one. The test is frequently punctate." 



"Locality. — Common all through the Chazy limestone at Chazy,. 

 \'alcour Island, Crown Point, and elsewhere in the Champlain \'alley.'* 



