320 PROCEEDINGS OF THE ACADEMY OP [1885. 



1884. Archaeocrinus desideratus Walter B. Billings MS. (The description will ap- 

 pear in the Trausactiona of the Field Naturalist's Cluh of Ottawa.) 



Archseocr. globularis Nichols, and Ether., Silur. Fossils Girran Distr., p. 

 329, PI. 22, figs. 9 11. Craighead limestone. 



I :'. Archaeocrinus sculptus (S. A. Miller), Lyriocrinus sculptus, Cincin. Journ. 

 Nat, Bist., toI. r, p. 217, PL 3, figs. 6 a, b. — Trenton limest. Kuoxville, 

 Tenn. 

 Si/ii. Lyriocrinus sculptilis S. A. Miller. Name preoccupied. 



RHAPHANOCKINUS nov. gen. 



"■"i'»„ ;i radish; xplvov, a lily.) 



Syii. Glyptocriinix Waleott (in part), not Hall, 1883, New Spec, of 

 Foss. from Trenton gr. of N. York, p. 0. (Abstract from the 35th 

 Rep. N. York State Museum Nat Hist., N. York.) 



The species upon which the genus Iiliaphanocrinus is pro- 

 posed, was referred by Waleott, with some doubt, to Glyptocri- 

 nus. Like that genus, it has regular^ 7 arranged interradial plates, 

 but these rest upon the truncate upper side of the basals, not 

 upon the sloping sides of the first radials as in that genus ; 

 besides it possesses underbasals. The latter plates were not 

 observed by Waleott; they ai'e evidently small, and covered by 

 the large column or hidden within the basal concavity. That 

 underbasals were present, is clearly seen by the angular form of 

 the first radials, and b} r the form, size and position of the basals. 



Rhaphanocrinus is closely allied to Archaeocrinus, from which 

 it differs in having the arms constructed of a single series of 

 quadrangular plates, and in having simple, in place of branching, 

 arms. It also resembles Dimerocrinus in its general aspect, but 

 is readily distinguished by the position of the interradial plates, 

 and by having the arms constructed of a single series of plates. 

 It differs from Anthemocrinus, with which it has probably the 

 closest affinities, in the entirely distinct arm structure. 



Generic Diagnosis. — Calyx short, truncate below ; interradial 

 spaces slightly depressed. 



Underbasals small, not visible in a lateral view, and more or 

 less hidden by the column. Basals large, hexagonal, the upper 

 side truncate for the reception of the first inlerradials. 



Primary radials :i 5, Large ; the first and third marly alike in 

 form. Secondarj radials two or more, quadrangular ; gradually 

 decreasing in height and passing into arm plates. 



Interradials numerous; those of the ventral side smaller. Inter- 

 axillary plates few. Summit plates, and form of anus unknown. 



