Description of Seven j^eic S2>ecies. 255 



downward at the bending of the lateral lol3es, and were evidently tu- 

 berculated at this point. The}' are strongly grooved. 



Pygidium — The pygidium is subtriangular, a little wider than long, 

 and the test evidentl}' terminated in a spine. The axis is depressed 

 convex, has eighteen aunulations, and a central row of four tubercles, 

 arranged as follows: commencing at the posterior part, and counting 

 the anuulations forward, a tubercle is found upon the 4tli, 7th, 11th and 

 14th aunulations. There are six pleura? on each side directed out- 

 ward, and graduall}' curving backward. Each pleura bears a node 

 near the dorsal furrow, and another near the margin. 



The species is founded upon casts from the magnesian limestone of 

 the Niagara Group, at Joliet, Illinois. This is the first attempt to de- 

 scribe, from American strata, vlvlj fossil in this genus, from an3'^thing 

 like complete specimens. Nearly all the species have been founded 

 upon the pygidia alone. None of the species that have been described, 

 however, bear much resemblance to this one, except Encrinarus orna- 

 ttis, and it is very readily distinguished. The aunulations, the pleurae, 

 and the tubercles are more numerous in the E. ornatus than they are 

 in this species, and the tubercles do not occupv corresponding aunula- 

 tions in the two species. 



The specimens illustrated are from the magnificent collection of W. 

 C. Egan, Esq., of Chicago, Illinois, in whose honor I take great pleas- 

 ure in proposing the specific name. 



Cyathocrinus harrisi, n. sp. 



Plate XV., fig. 2, view of the anterior or azygos side, and part of the column, natural size. 



Body, cup-shaped, about twice as wide as high, and ornamented b}" de- 

 pressions at the corners of the plates, and rounded or subangular ridges 

 between them. Sub radials, hexagonal, except the one on the azj'gos 

 side which is heptagonal, and a little larger than the others. First 

 radials, wider than high, pentagonal or sub-pentagonal, with the longer 

 side uppermost. The two anterior arms bifurcate on the fourth free 

 arm plate. The facet for the reception of each radial is only about 

 half the breadth, of the upper face of the radial. The plates are slight- 

 \y constricted and rounded in the middle, and much flanged at the 

 upper part, presenting an appearance somewhat similar to a series of 

 small, short spools, piled one upon another, and graduall}^ diminishing 

 in size. Our specimen does not show the second bifurcation of these 

 arms. There is a short, strong pinnule springing from each side of 

 each arm plate above the first bifurcation. Below this, I suppose the 



