From the Niagara Formation. 



69 



aperture are wanting. The grooves for the attachment of the tenta- 

 cular are distinctly preserved, but no appendages have been seen. 



This form diifers from Stephanocrinus gemmiformis in its nar- 

 rower proportions and more acute base, and also in the smaller and 

 less elevated plates of the third series, of which one plate is con- 

 spicuously larger than the others. 



In the structure of the body, at least, there are no differences which 

 appear to be of generic importance between Stephaxocrixus and 

 CoDASTER. The species under consideration presents all the es- 

 sential features of the former genus. 



God ASTER PENTALOBUS 71. Sp. 



Body robust, distinctly pentangular and pentalobate in the upper 

 part, narrowing below ; the basal portion unknown. Summit broad, 

 the ambulacral areas prominent. 



The specimen described has a width of over ten ram. in the upper 

 part ; and the wddth of each side, measured from the base of the 

 ambulacral areas, is about seven mm. 



A single imperfect specimen only, has been observed, but its char- 

 acters are quite distinctive, when compared with any Silurian 

 forms of the genus. 



BRACHIOPODA. 



LiXGTJLA GIBBOSA 71. Sp. 



General form subelliptical, lateral margins curving, rounded at the 

 base, and somewhat abruptly contracting towards the beak ; valves 

 gibbous on the umbones; greatest convexity at about one-third the 

 length from the apex. Surface marked by fine irregular concentric 

 striae which in some parts become lamellose, and also by concentric 

 undulations. 



Craxia spixigera 71. sp. 



Shell very broadly oval, wider than long, slightly concave on the 

 margin near the apex. Upper valve depressed subcorneal, apex trans- 



