120 



NEW YORK STATE MUSEUM 



brachioles. Respiration by means of hydrospires crossing one or 

 more interambulacral plates, the water flow passing down the 

 brachioles into a series of brachiolar cavities from which the hydro- 

 spires are reached through pores passing between the adambulacrals. 



Pachyocrinus crassibasalis Bill. 



Can. Org. Rem. Decade IV. p. 22, pi. r- fig. 3 a-b 



The wing plates of Blastoidocrinus and its closely terminal anus 

 remind one strongly of some species of Eucalyptocrinidae and the 

 resemblance is no doubt due to homoplasy. As we have in the 

 Chazy limestone a form of crinoid which may also have possessed 



Fig. 4 To the left, a reproduction of an -untouched photograph of Pachyocrinus 

 crassibasalis. To the right, a portion of same with the sutures lined with ink. It will 

 be seen that the specimen has but four basals. The five heavy radials still have their upper 

 edges buried in the matrix. 



similar plates and as Mr Billings immediately followed his descrip- 

 tion of Blastoidocrinus with this still more difficult puzzle it may 

 not be out of place for me to here again call attention to this 

 neglected species. 



From the accompanying cut [fig. 4] it will be seen that this form 

 has four basals, not five as Billings describes and figures it. Fig- 

 ure 4 is reduced from- a photographic enlargement of the type speci- 

 men, the portion of the figure to the left is untouched, at the right 

 is a part of a print from the same negative with the sutures darkened 

 with ink. Billings says of the heavy plates that they " may be 

 either subradials or first radials/' which in our modern terminology 



