The Calceocrinidce. 393 



lary, and the posterior arm having three, the first of which enters into 

 the formation of the posterior side of the calyx with the brachial of the 

 opposite side. The latter brachial, with the elongate azygous, supports 

 the anal plate, which in turn supports the other plates forming the ven- 

 tral tube. 



Type of genus, Gastocrinus furcillatus W. E. Billings. 



I wish here to express mj indebtedness to Walter R. Billings, 

 Esq._, of Ottawa, Canada, who very generously placed his types 

 and all the specimens of the genus in his possession at my dis- 

 posal for the purpose of study. 



Below will be found a few remarks on C. furcillatus, noting 

 several points not given in the original description, they having 

 been obscured by adherent shale till the specimen came into my 

 hands. 



Castocrinus furcillatus W. R, Billings. 

 PI. X., Fig. 1. 



Calceocrinus furcillatus W. E. Billings. 

 The Ottawa Naturalist, Vol. I., No. IV., p. 51. 



The anterior basalsare prolonged to, and form a part of, the columnar 

 facet, not stopping short of it, as represented in the diagram accompany- 

 ing the original description. 



The azygous is elongate and narrow, and extends from the basal 

 plates to the anal plate, the inner corner of which it supports on its 

 sloping upper side. It lies to the left of the median line ; the larger of 

 the two posterior brachials — the right — extending up to this line. The 

 inner corner of this brachial is also prolonged upwards beyond the azy- 

 gous and rests against the inner side of the anal plate. 



The incurved margin of the consolidated basal piece is evenly rounded 

 and meets in a narrow connecting band beneath the column. 



Trenton formation, Ottawa, Canada. Type in the collection 

 of W. E. Billings. 



Castocrinus rugosus W. R. Billings. 

 PI. X., Fig 3. 



Calceocrinus rugosus W. E. Billings. 

 The Ottawa Naturalist, Vol, I., No. IV., p. 53. 



The position of the consolidated basal in the type specimen is evi- 

 dently abnormal, as the plates of the posterior side seem to have been 

 pulled downward after it, and out of their proper positions. This was 

 probably caused by the hgaments, which united the two together in 



