380 P. E. Raymond — Fauna of the Chazy Limestone. 



OSTRACODA. 



Leper ditia limatula sp. no v. 



Length 10'5 mm ; height 7'5 mm . 



Length 9 mm ; height 6 mm . 



Length 9*5 mm ; height 6.25 mm . 



Length 9.5 mm ; height 7*5 mm . 



Shell of medium size, a little smaller than Leperditia f abil- 

 ities, oblong in outline, higher behind than in front. Hinge 

 short, straight. Anterior end regularly rounded. The poste- 

 rior end slopes back almost straight for a short distance, but is 

 broadly rounded on the lower posterior margin. The eye 

 tubercle is small, on some specimens sharp, on others obscure. 

 It is situated in the anterior angle, above and a little in front 

 of the " muscle spot." The latter is large, circular, and very 

 finely reticulated. Back of the muscle spot is a region of the 

 shell which is covered with fine raised lines radiating from the 

 side of the spot. These lines frequently anastomose, making 

 a very pretty reticulate surface. The muscle spot is raised 

 above the general surface of the carapace on the lower poste- 

 rior side, where these lines originate, but the upper and ante- 

 rior sides are level with the main part of the shell. 



The right valve overlaps the left valve considerably, espe- 

 cially along the ventral edge, which is abruptly deflected and 

 usually shows a low short ridge right at the keel. The lower 

 margins of the anterior and posterior ends are flanged. The 

 border is very narrow and is marked by small pits, which 

 increase in size ventrally. On one finely preserved specimen 

 the anterior flange shows 8 pits, of which the seventh, counted 

 from the front, is largest, and the eighth is very small. On 

 the posterior flange of the same specimen there are 10 pits, 

 the eighth from the posterior end being the largest, the ninth 

 a little smaller, and the tenth minute. The left valve is not so 

 high in proportion to the length as the right valve, but it is 

 also abruptly deflected ventrally. It shows neither anterior 

 nor posterior flanges and there is a small projection close to 

 the hinge line and parallel to it. Below this is a slight 

 depression. 



Locality. — Common on Valcour Island in certain localities. 

 Rare at Valcour and Chazy, New York. 



Primitia latimarginata sp. nov. 



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 



