II. Edrioaster Buchianus. 



1900 203 



Edrioaster Bigsbyi, 1858. Ill the list on p. 262 of the same work 

 it is actually called " Edrioaster Buchii (Agelacrinics, Forbes)." The 

 same is the case in Etheridge's revision of Salter (pp. 481 and 395). 



Salter's opinion is abundantly justified not only by the details of 

 the present paper, but by the new facts concerning Edrioaster 

 Bigsbyi, which will form the subject of the next study. To that it 

 is better to postpone the diagnoses of the genus and of the present 

 species. 



EXPLANATION OF PLATES VIII, IX, and X. 



Edrioaster Buchianus. 



[All the figures are from the tvpe-specimeu in the Museum of Practical Geology, 

 except PL X, Fig. o, which is from a fragment associated with it. Plates VIII 

 and IX are based on photographs by Mr. J. Green ; the figures of Plate X are 

 drawn directly from the specimens or from wax squeezes thereof. The figures of 

 Plates VIII and IX are magnified two diameters ; those of Plate X are enlarged 

 to the extent stated under each. Difficulties of lighting have rendered impossible 

 a rigorous maintenance of the standard orientation ; where doubt might have arisen 

 the position of the anal interradius has been marked by a *.] 



