BRA CHIOPODA — TELOTREMA TA. 



289 



o <» 



Helderbergian of New York, New Brunswick and Nova Scotia. 



LXXVIII. Leiorhynchus Hall. 

 Similar to Camarot&cJna but with the plications on the median 

 fold and sinus highly developed while those on the lateral slopes 

 are slightly developed or wanting. Shell substance thin. Dev.-Miss. 



260. L. mysia Hall. (Fig. 356.) Devonic. 

 Very small, usually not exceeding 3,£ inch in diameter, with 



almost circular outline and with proportionally very strong plirn- 

 tions of which there is at least 

 one in the sinus with at least 

 three on each side of it. 

 Marcellus of New York. 



261. L. limitare (Vanuxem). 



(Fig. 357, a-b.) Devonic. 



Small, gibbous, with mesial si- 

 nus and fold developed toward 

 the front. Plications on fold and 

 sinus bifurcating. Surface plica- 

 tions covered with fine concentric striae. 



Marcellus of New York, Ohio. 



262. L. laura (Billings). (Fig. 357, c.) Devonic. 

 Length and greatest width nearly equal. Sinus and fold marked 



with 3 to 7 rounded plications, all bifurcating. Concentric striae 

 present. 



Marcellus-Hamilton of New York, Nevada, Ontario. 



Fig. 356. Leiorhynchus mysia (Pal. 

 N. Y. IV.). 



Fig. 357. a-h, Leiorhynchus limitare ; c, L. laura; d, L. quadricostatum. 



263. L. quadricostatum (Vanuxem). (Fig. 357, d.) Devonic. 



Broadly ovate. Plications of lateral slopes very faint. Sinus 

 and fold marked with 3 to 5 rounded plications. ' 



Genesee of New York, Indiana, Kentucky, Nevada. 



