52 



Family ICTHTHYOCRINID^. 



LECANOCRINUS GREENEI, n. Sp. 



Plate III, Fig. 28, azygous side view of body, arms, and part 



of the column. 



Species medium size; general form, with the arms closed, 

 obovate Surface smooth or granular. Column composed of 

 rather thick plates. 



Basals form a low cup having a diameter at the top nearly 

 one half greater than the diameter of the column and truncated 

 below the full diameter of the column. Subradials large, nearly 

 as long as wide and gradually expanding. First primary ra- 

 dials of unequal size and about twice as wide as long. Second 

 primary radials short, quadrangular, one-third as large as the 

 first, three or four times as wide as long. Third primary 

 radials a little larger than the second, pentagonal, axillary, 

 and bear upon each upper sloping side the secondary radials. 

 The number of secondary radials is not uniform. In one of 

 the rays shown in our specimen there are three secondary 

 radials and in the other three rays there are four secondary 

 radials, the last being axilliary, which gives to the species 

 twenty arms. Some of the arms probably bifurcate again. 



There is an. elongated, octagonal interradial plate on the 

 right side of our specimen, resting between the superior slop- 

 ing sides of a first primary radial and a second primary radial, 

 and separating the primary radials and one secondary radial, 

 on one side, from the second and third primary radials and 

 the first and second primary radials, on the other. An inter- 

 radial may be seen on the left side of the specimen that ap- 

 pears to occupy the same position. The azygous interradial 

 broadly truncates a large subradial and separates the primary 

 and first secondary and part of the second secondary plates, 

 that abut against it, giving to it eleven sides. If there are 

 two azygous plates in this species, as is usual in the genus, 

 the suture, that separates one from the first primary radial on 

 the right, is obliterated, in our specimen. 



The regular interradials, in this species, constitute a marked 

 peculiarity, the azygous plate too is different from all others. 

 It may also be distinguished by its general form. 



Found by George K. Greene, in whose honor the specific 

 name is given, in the Niagara Group near Louisville, Ken- 

 tucky, and now in the collection of Wm. F. E. Gurley. 



