PLATYCRINID^. 735 



the outer ends to the sides of the fiicets sh'ghtlj truncated by the first inter- 

 radial plate, which is strictly interbrachial, rising only to the top of the first 

 distichals. Costals small, as long as wide, trigonal, the sides convex; they 

 occupy a third of the radial facets, the other two thirds being occupied by 

 the distichals. Distichals two; the first a little larger than the costals, 

 those of the same ray meeting above the latter. Second distichals sub- 

 quadrangular, separated from the first by a deep groove ; their outer edges 

 distinctly excavated at the upper end, forming a well defined, semicircular 

 facet for the reception of the arms, which face nearly horizontal. Second 

 distichals separated interradially by two very small interbrachial plates. 

 Arms two to the ray; their structure and that of the ventral disk unknown. 

 Horizon and LocalUy. — Niagara group ; near Greenville, Darke Co., and 

 at Cedarville, Greene Co., Ohio. 



Type in the collection of Rev. H. Hertzer of Berea, Ohio. 

 Remarks.— The description and figure were made by Hall from a gutta 

 percha impression of a natural mould in the rock. The specimen figured 

 on Plate LXXV., Pig. 14, may represent a Marsupiocrinus, but is more 

 probably, we think, a Culicocrinus. It was found in the Niagara at Maquo- 

 keta, Iowa. 



CORDYLOCRINUS A.v 



GL. 



1878. Angelin ; Iconogr. Criuoideorum Suecu-e, p. 3. 



1879. ZiTTEL; Handb. der Palieontologie, Vol. I., p. 365. 



1881. W. and Sp. ; Rerision, Part II., p. 60 (Proceed. Aead. Nat. Sci. Pliila., p. 234). 



SjTi. Platyerims (iu part) — Phillips ; Murcliisoii's Siluria, 2d ed., Plate 14, Fio-. 9. 



Angelin defines this genus as follows-: "Basaha tria, connata. Radialia 

 primaria permaxima, cetera magnitudine multoties superantia ; secundaria 

 et tertiaria transversa. Interradialia in tribus verticillis. Brachia quin- 

 que bidigitata, pinnulae longLssimse." He j^laces the genus under the 

 PlatycrinidiB, and refers to it a single species from Gotland, of which 

 he gives a figure. This species has close affinities with the three Amer- 

 ican species which Hall (Paleontology New York, Vol. II., pp. 113 to 

 116) described as Plati/crinus plumosus, P. parvus, and P. ramiilosus. 

 The latter undoubtedly are generically identical with a small form from 

 the Wenlock group of Dudley, known under the name of Platycrinus 

 retiarius Phill, and with two other undescribed species which also occur 

 in the neighborhood of Dudley : one with four arms to the ray, the other 



