CANADIAN FOSSILS. 45 



Pal^ocrinus angulatus, Billings. 

 Plate III. Figures 6a, 66. 



(DENDEOCEiNiTS AHGULATUS, Report Geological Survey of Canada, 1856, page 269.) 



Description. — In this beautiful little crinoid the plates are omar 

 mented with radiating ridges similar to those of Glyptocrinus decadac- 

 tylus. The cup is small, conical and pentagonal. From the centre 

 of each of the rather large sub-radial plates there proceed six 

 strongly-elevated ridges, one to the base of each of the two arms 

 above the plate, one to each of the two basal plates below it, and 

 one to each of the adjoining sub-radials. The arms are very slender, 

 sharp on the back, and at least twice divided ; the three joints of 

 the column which remain attached to the specimen are pentagonal. 

 Length of cup, three lines ; breadth at the margin, four lines. 

 Diameter of column, nearly one line. 



Explanation op Figures. Plate III. 



Figure 6a. Left side of the only specimen discovered. 

 " 66. Column, enlarged. 



Locality and formation. — Trenton limestone, City of Ottawa. 



PALiEOCRINUS EHOMBIFERUS, Billings. 



Description. — This species is of nearly the same shape as P. angu- 

 latus, but differs in the arrangement of the surface-markings. In 

 P. angulatus the radiating ridges are so disposed as to encircle the 

 body with two horizontal rows of triangular spaces. In this species 

 however, in consequence of the absence of the transverse ridges near 

 the centre of the body, the spaces are rhomboids instead of triangles. 

 The ridges are also so broad in the base that the separate plates 

 appear to be simply bevelled from the centre to the edges. The 

 detached plates figured on plate 4, vol. i. Palaeontology of New York, 

 under the name of Actinocrinus, resemble the sub-radials of this 

 species, but are larger. Only one specimen has been collected, 

 consisting of a perfect cup imbedded in a piece of limestone. The 

 arms are sharp-edged on the back, and twice divided. Length of 

 cup, three lines ; and of the arms, nine lines. 



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



