340 PROCEEDINGS OF THE ACADEMY OF 



various species of the two groups can be as readily separated, even without 

 specimens showing the arms, as those of any other two allied genera. Indeed, 

 they can be far more readily separated than Scaphiocrinus and Zeacrinus, or 

 than the former can in all cases be separated from Poteriocrinus. 



Believing that a systematic classification of the Crinoidea really requires the 

 separation of the group under consideration from the types for which the name 

 Cyathocrinus Avas originally proposed, we cheerfully adopt for it Mr. Wach- 

 smuth's appropriate manuscript name, Barycrinus. Mr. Wachsmuth refers to 

 this group the following species, the first of which he regards as the typical 

 form, — viz. : B. spurius, B. crassibrachiatus, B. huUatus, B. tumidus, B. vtagister, 

 B. Hoveyi, B. latua, B. Lyoni, B. sculptilis, B. Thomne and B. protuberatis, all de- 

 scribed by Prof. Hall under the name Cyathocrinus ; also B. cornutus [zz=Cyatho- 

 crinus cornutus, Owen and Shumard). 



We likewise place in this group our B. Wachsmuifn, B. angulatus and B. sub- 

 tumidus, all of which were originally described by us under the name Cyatho- 

 crinus. It is possible our Cyathocrinus ? Sangamonens may belong here, as it 

 has the same thick body plates, as well as the small quadrangular intercalated 

 subanal piece. Still, as all its first radial pieces are evenly truncated, their 

 entire breadth straight across above, and provided with a transverse furrow, as 

 if for the articulation of the second radials, it is probable these and the succeed- 

 ing radials and arms (which are unknown) had a different structure and 

 arrangement. It is certainly not a true Cyathocrinus, however, as properly re- 

 stricted, but more probably belongs to an undescribed genus. 



Barycrinus magnificcs, M. and. W. 



Body attaining a gigantic size, cup-shaped, or widening rather rapidly, with 

 moderately convex sides from the column to the. top of the first radials. Base 

 shallow, basin-shaped, or about four and a half times as wide as high, with a 

 large concave facet for the attachment of the column, and a large, obscurely 

 five-lobed perforation for the connection of the central cavity of the column 

 with the visceral cavity of the body. Basal pieces regularly pentagonal. Sub- 

 radial plates about five or six times as large as the basal pieces, as wide as 

 long or slightly wider, all regularly hexagonal, excepting one on the anal 

 side, which is a little shorter than the others, and truncated above for the re- 

 ception of the anal piece, so as to present a general heptagonal outline. First 

 radial pieces about one- third wider than high, and larger (particularly wider) 

 than the sultradials, each presenting a general pentagonal outline, and pro- 

 vided with a rather shallow, outward sloping, concave facet, occupying more 

 than one-third its entire breadth, for the reception of the succeeding radials. 

 Second radial pieces very much smaller than the first, extremely short, or only 

 about one-fourth as long in the middle as wide, and becoming much thinner, 

 or wedge-shaped, on each side. Third radials a little longer in proportion to 

 their breadth than the second, and presenting a subtrigonal outline, supporting 

 on their sloping upper sides, broad, short, rounded arm-pieces. Anal piece 

 about half as wide, and nearly of the same length as the first radials, and 

 subquadrangular in form. Surface marked with small pustules, which oftep 

 become confluent, so as to produce a peculiar corrugated roughness, some- 

 what similar to the ornamentation we see on the bod}' plates of the true 

 Amphoracrinus, but coarser. 



Breadth of body3-33 inches; height of do., 2-20 inches; breadth of base, 0-60 

 inch ; breadth of facet for the reception of the column, 0-85 inch ; do. of largest 

 first radial piece, 1-70 inches; height of same, 1-30 inches. Thickness of one 

 of the arms at base, 0-70 inch. 



This splendid Crinoid was found by Mr. Green, of the Illinois Survey, with 

 its plates detached and lying near together in the rather soft matrix. After 

 working out the pieces, we succeeded in building up the entire body to the 

 third radials and first arm-pieces, inclusive, excepting the anal piece, which 

 was not found. It presents a very striking appearance, and is the largest Cri- 



[Dec. 



