104 



Deseription.—Yerj small, elongate, conical, slender, slightly curved, 

 often in more than one direction ; radiating septa alternating in size, about 

 fourteen of the larger with an equal number of the smaller, at the mar^ 

 of individuals of the average size. Surface with a few obscure undulations 

 of growth. Cup moderately deep. 



Length, from 3 to 4 lines ; width of the cup at the margin, about 1 

 line ; depth of the cup, from i to I of a line. 



This little species occurs in immense numbers in the Middle Silurian on 

 the Island of Anticosti. 



Locality and Formation. — Challoupe River, Anticosti ; division 4, 

 Middle Silurian. 



Collector. — J. Richardson. 



Petraia latuscula. (N. sp.) 



Fig. 92, a, b. 



Description. — Corallum of medium size, short, turbinate, nearly straight 

 slightly curved towards the base, expanding to a width of from 8 to 10 

 lines in a length of from 5 to 8 lines, then becoming cylindrical or nearly 

 so. Cup rather deep. Radiating septa, as indicated by the external 

 markings, about 50. Surface with a few obscure imdulations of growth ; 

 the longitudinal striae representing the septa are usually obscure, but in 

 some specimens distinctly marked. 



The most abundant specimens are from 5 to 10 lines in length, and from 

 8 to 10 lines in width at the margin. In one specimen 13 lines in length, 

 the width of the cup is 10 lines and the depth 5 lines. 



Locality and Formation. — The Jumpers, Anticosti ; division 4. Mid- 

 dle Silurian. 



Collector. — J. Richardson. 



