34 CANADIAN FOSSILS. 



over the suture between the anterior and left anterior sub-radials, 

 and having above it on one side the large a^ygos, and on the other 

 the left anterior primary radial ; several small pectinated rhombs, 

 similar to those of the Cystideas. 



The characters of this genus are nearly the same as those of 

 Cyathocrinus, Foteriocrinus etc., but differs from these and other allied 

 genera in the presence of the pectinated rhombs. Only one species- 

 is known. 



FoROCRiNus CONICDS, Billings. 

 Plate II. Figure 5a-5d. 



(P. CONIC03, Report Geological Survey of Canada, 1856, page 2t9.) 



Description. — Cup, one line and a half in diameter at the base, and 

 gradually enlarging, with slightly ventricose sides, to the width of 

 five lines at the margin ; height, seven lines ; basal plates narrow, 

 nearly two lines high ; sub-radials, three lines in height ; first primary 

 radials, about two lines and a half in height and breadth ; all the 

 plates smooth ; column, circular, smooth, and suddenly enlarged near 

 and up to the base of cup, composed of very thin joints ; free rays^ 

 long, slender and single to their extremities ; they are about half a 

 line in thickness, and appear to be composed of a single series of 

 joints. Only about one inch in length of the column next the base 

 has been seen. 



In this species there exists a number of poriferous areas resembling 

 the pectinated rhombs of the Cystideas in their structure, and probably 

 adapted to the performance of the same functions. Their forms and 

 position are however somewhat different from those of any known 

 cystidean. In fossils of the latter order these organs consist of twa 

 parts, one situated upon each of two contiguous plates, but in this 

 crinoid, each is so placed that it occupies the angles of three plates. 

 Their form is that of an equilateral spherical triangle, and their size 

 about one line in diameter. There are five situated at the apices of 

 the five basal plates, five at the lower angles of the arm-plates, five 

 at the apices of the sub-radials and five between the arm-plates on 

 the margin of the cup. There are also two or three small ones at 

 the angles of the azygos-plates, in all twenty-two or twenty-three. 

 The pores consist of fine elongated parallel slits, which appear to 

 penetrate through the plates j they are not at right angles to the 

 margin of the plates as in the Cystideae, but oblique. 



