KEVTSION OF PALEOZOIC STELLEROIDEA. 239 



gi-oovo, and which, closely uniting by then- margins, give a t(u-(^ti- 

 form termination of nearly one-third the entire length, each one 

 having the aspect of a slender crinoidean proboscis. 



" Geological formation and locality. — In the Hamilton group, near 

 Fenner, in Madison County, New York. The spcicimen was collected 

 during the geological survey, and is now in the vStatc Museum." 



EUGASTERELLA (?) CONCINNA (Ringueberg). 



Eugaster concinnus Ringueberg, Bull. Buffalo Soc. Nat. Sci., vol. 5, 1886, p. 8, 

 pi. 1, fig. 3. 



This species does not belong to Eugasterella, but until the holo- 

 type is restucUod it can remain in this genus. It is from the Rochester 

 shale at Lockport, New York, and is in Dr. Ringueberg's collection. 



Original description. — ''Disk flat, thin, alated, composed of very 

 fine granulose plates. Rays broad at their base; flattened, rapidly 

 tapering for two-thirds of their length; terminal third attenuate, 

 rounded; plates, if any, undefinable. 



''Dorsal side with four series of plates; two mecUan and two lateral ; 

 the transverse sutures dividing the outer series are continuous with 

 every other transverse suture dividing the central series. Medial 

 series vdih t-wice the number of plates of the outer, and are raised 

 above them. 



"Sutures depressed. Surface of the plates rounded and finely 

 granular. 



"The lateral series of plates decrease regularly in size after reach- 

 ing the disk until they end in a pronounced elevation formed by the 

 last pair of the medial series at a point about haKway from the 

 border toward the center of the disk — measuring at the narrowest 

 part — where both series end. Between these elevations the disk 

 has a shallow, stellate depression \nth the points opposite the several 

 rays. The two outer rows of plates apparently disappear toward 

 the attenuate tip before the median does so. The imperfect cast 

 of the upper part of one of the rays is all that is known of the ventral 

 side; this shows traces of an alternating series of ambidacral plates. 



"Marginal plates spiniferous. 



"Length of ra}^, one-half inch." 



Genus PTILONASTER Hall. 



Ptilonaster Kall, Twentieth Rep. N. Y. State Cab. Nat. Hist., 18G8, pp. 291-292; 



rev. ed., 1808=1870, p. 334.— Lutken, Dansk. Vid. Selsk. Skrift., ser. 5, 



vol. 8, pt. 3, 1869, p. 82.— Sturtz, Palaeoiitographica, vol. 32, 1886, p. 83; 



N. Jahrb. fur Min., etc., 1886, vol. 2, p. 152.— Gregory, Proc. Zool. Soc. 



London for 1896, 1897, p. 1036. — Sturtz, Verb, naturli. Ver. prcuss. Rheinl., 



etc., vol. 56, 1900, p. 188. 

 Palxocoma Miller (part), N. Amor. Geol. Pal., 1889, p. 260. 



Original description. — "Form and general features as in Eugaster, 

 but differing in the plates of the rays. Rays composed of an ambu- 



50601°— Bull. 88—15 16 



