46 



S. BREVis, B., Can. Nat. Geol. vol. iv, p. 135. — South-west Point; 



Div. 4, A. G. 



Genus Atrypa, Dalman. 



A. RETICULARIS, Linn. — Occurs throughout the Anticosti Group, but 

 most abundant at South Point. 



A. MARGiNALis, Dalman. — The specimens are in general more rotund 

 and wider on the hinge Une than those from Wenlock. Junction CliflF; Div. 

 1,A. G. 



Genus Zygospira, Hall. 



Z. PAUPERA, n. sp. — Shell small, ovate, width greater than the length ; 

 sides nearly uniformly rounded ; front margin gently convex or with a por- 

 tion in the middle sometimes slightly concave, straight, or gently projecting. 

 Ventral valve convex, regularly arched from beak to front, concave towards 

 the cardinal angles and sides ; beak small, closely incurved. Dorsal valve 

 gently convex with a very wide concave mesial sinus dying out near the 

 umbo ; compressed at the cardinal angles. Surface with about twenty-five 

 small angular ribs. Width 4 lines ; length 3 lines. Near Jupiter River ; 

 Div. 3, A. G. J. Richardson. 



This species closely resembles Z. Modesta, the type of the genus, but is 



smaller. 



Genus Athyris, McCoy. 



A. UMBONATA, B., Pal. Foss., vol. i, p. 144. Junction Clifi"; Div. 1, A. 

 G. 



A. Prinstana, B., op. cit., p. 145. — Prinsta Bay ; Div. 1, A. G. 



A. Julia, B., op. cit., p. 146. The Jumpers ; Div. 4, A. G. 



A. JuNiA, n. sp. — Shell small, orbiculo-pentagonal, both valves convex, 

 width almost equal to the length. The sides in the rostral third are 

 nearly straight and converge to form an angle at the apex of about 100° 

 degrees ; in the middle third rounded ; in the lower third somewhat 

 straight and converging to the mesial fold ; the ventral margin straight in 

 the median third or for the width of the fold and sinus. Ventral valve ra- 

 ther strongly convex, uniformly arched from beak to front : umbo mode- 

 rate ; beak small, closely incurved over the umbo of the dorsal valve ; me- 

 sial sinus deep and concave ; at the front margin about one-third the whole 

 width, dying out near the umbo ; bounded on each side by a strong rounded 

 fold, outside of which an obscure sinus nearly as wide. Dorsal valve less 

 convex than the ventral ; umbo moderate ; beak buried under that of the 

 ventral valve ; a strong mesial fold narrowly rounded along its crest with 

 a deep subangular sinus on each side, all dying out a little above the mid- 

 length. Surface apparently smooth but in some specimens exhibiting 



