258 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 



the two series of the same ray are so nearly in contact as to leave but a nar= 

 row space for the insertion of interdistichals. First distichals somewhat 

 longer than the succeeding ones, which are quite short; the fourth is axil- 

 lary, giving off to the outer sides a row of palmars, which are free from the 

 third or fourth plate; to the inner side two palmars, of which the upper 

 is axillary, and supports two arms, making three arms to each side of the 

 ray. Arms subcylindrical, stout, very little tapering; composed at their 

 bases of a few quadrangular pieces, followed by cuneate ones, wdiich deeply 

 interlock. Pinnules strong, given off nearly at right angles, and composed 

 of short joints ; the first very much stouter than the others, given off from 

 the second distichals, and w^holly or partly incorporated into the calyx. 

 Interradial spaces wide, the upper portions rather deeply depressed. The 

 plates of the tw^o lower ranges very large, the first being the largest plate in 

 the calyx. There are probably ^ve or six rows above, but the number 

 of plates in each row is extremely variable; the third contains variously 

 from three to five plates at the regular sides, and from four to six at the 

 anal side ; the fourth row has as many as eight in some specimens. The 

 first plate of the anal side is somewhat larger than those of the regular 

 sides ; it is octagonal, its upper angle being slightly truncated for the recep- 

 tion of a narrow anal plate, which is placed between two interbrachials. 

 Interdistichals from one to three, longitudinally arranged. Ventral disk 

 rather flat, composed of very small irregular pieces ; the ambulacra subteg- 

 minal, except near the arm bases, but the course of the ambulacra is marked 

 by high ridges which diverge to the arms, and form deep depressions all 

 along the interambulacral spaces. Orals apparently unrepresented, the sum- 

 mit being covered by similar small plates to the rest of the disk. Anal 

 opening subcentral, at the top of a well defined protuberance. Column 

 round ; axial canal large, pentalobate, the outer ends of the lobes widest 

 and truncated. 



Horkon and Locality. — Trenton limestone; Ottaw^a, Canada. 

 Types in the collection of Mr. Walter R. Billings, Ottawa. 



RHAPHANOCRINUS W. and Sp. 



1885. W. and Sp. ; Revision, Part HI., p. 98 (Proceed. Acad. Nat. Sci. Pliila., p. 320). 

 1887. Oehleet ; Ann. des Sci. GeoL, Tome XIX., Plate I., Pigs. 10, 11. 

 1889. S. A. Miller; North Amer. Geol. and Palaont., p. 277. 



Syn. Glyiptocrinus (in part) — W^alcott ; 1883, New Spec. Poss. of the Trenton group of New York, 



p. 2 (Abstr. from the 35th Rep. New York State Museum Nat. Hist,). 

 Syn. Glyptocrinm imi^^xX) — %. A. Miller; Journ. Cincin. Soe. Nat. Plist , Yol V. p 37 and 

 ibid., 1883, Yol. YL, p. 224. • , i^. , 



