20 



crinoid there is a depression below as well as above, so that it is often diffi- 

 cult to say which is the cup or wliich tlie base. The transverse polished 

 section shows numerous radiating tortuous channels, often branching, from 

 half to one line in diameter, and usually distant once or twice their Avidth. 

 The vertical section shows other channels ascending and sloping outwards. 

 The weathered surfaces are irregularly striated with obscure rounded often 

 interrupted radiating ridges of from ^ to 1 line Avide. 



Some of the specimens are nearly flat, but in general they are obscurely 

 turbinate or very depressed pyriform. 



Locality and Formation. — Mhigan Islands, Chazy limestone. 



Collectors. — Sir W. E. Logan, J. Richardson. 



ASTYLOSPONGIA PARVULA. (N. Sp.) 



Description. — Small, gub-globular, the sides grooved by from five to 

 seven deep furrows, which divide it hito as many lobes. The furrows are 

 about half the width of the lobes. There is no trace of either a cup or a 

 pedicle at either extremity. The individuals are from |^ to | of an inch 

 in diameter. 



This species is of the same form as Roemer's A. inciso-lobota, with the 

 exception of the absence of the central depression or cup. It is also less 

 than half the diameter of that species. 



Locality and Formation. — City of Ottawa. Trenton limestone. 



Collector. — E. Billings. 



LiNGULA PeRRYI. (N. sp.) 



Fig. 23. 

 Fig. 23. — Lingula Pcrryi. Dorsal valve. 



Description. — Dorsal valve triangularly oval, the front margin gently 

 convex or nearly straiglit, the anterior angles broadly rounded, the apex 

 obtusely pointed ; the sides from the apex for one half the length, or a 

 little more, gently convex or somewhat straight and diverging at an angle 

 of about G0°. The beak is rounded, prominent and situated about ^ of a 

 line from the margin of the apex. The most convex part of the shell is 

 at about one filth the length from the beak ; from this point the surface 

 descends Vrith a uniform gentle and very slightly convex slope in all dii-ec- 



