1885.] NATURAL SCIENCES OF PHILADELPHIA. 329 



Iconographia, PI. 9, fig. 13, a malformed specimen of Eucalypto- 

 crinus, in which some of the arms divide half-way up to the top, 

 and in a similar manner, as in Corymbocrinus. Prof. Lindstrom, 

 of Stockholm, however, informs us that the plates along the ven- 

 tral side differ essentially in the two forms, and that the genus, in 

 his opinion, could not be arranged with the Calyptocrinidse. The 

 total absence of special anal plates, unites it with the Melocrinidae, 

 and in this we agree with Zittel, but not with Angelin. who sepa- 

 rated Corymbocrinus and Abacocrinus from 31elocrinus, and 

 placed them in separate families. The two genera have a similar 

 arm-structure, but differ essentially in the construction of the 

 calyx, the one having a strictly pentamerous, the other a decidedly 

 bilateral sj^mmetry. More close are the affinities with Polypeltes, 

 provided we understand that genus correctly. We are somewhat 

 in doubt whether Quenstedt's name Clonocrinus, should not be 

 adopted in place of Corymbocrinus, as it probably has priority, 

 but Quenstedt gives no generic description, only mentioning the 

 name in connection with a certain species. 



Generic Diagnosis. — Calyx basin, or low cup-shaped ; basal 

 portions broadly and deeply excavated ; plates of very uniform 

 size, rather heavy, somewhat convex, rarely ornamented ; sym- 

 metry regularly equilateral, except in the basals. 



Basals four, unequal, forming a hollow cone, which is filled by 

 the upper portions of the column. 



Primary radials 3X5, all wider than high. The first plate 

 larger than the rest, its lower (here inner) side forming a part of 

 the basal concavity, its opposite side at right angles with the 

 column, only a small portion curved upward. The second radials 

 quadrangular or nearly so, much wider than high, frequently with 

 convex lower edges, narrower than the first radials. The third 

 radials are pentagonal. Secondary radials 2X2X5, compara- 

 tively large. Their upper series support two rows of transversely 

 linear tertiary radials, arranged alternately like a double series of 

 arm plates, but connected b} r interradial and interaxillary pieces, 

 and hence forming parts of the body. 



Arms long, bifurcating, gradually tapering to the distal ends ; 

 from their base up composed of a double series of very short 

 but wide interlocking pieces. Pinnules long. 



Interradials arranged longitudinall}' in rows of a single plate 

 each. The first plate the largest in the cal} T x ; ninesided ; it ex- 



