316 PALiEONTOLOGY OF NEW-YORKi 



378. 2. SCHIZOCRINUS STRIATUS ( /;. sp.) 



Pl. XXVIII. Figs. 4 o, h, c. 



Body very gradually enlarging upwards ; plates narrow, elongated ; costal plates con- 

 sisting of a regular single series of five, supporting a series of scapular plates ; a single 

 range of intercostal plates, which are succeeded by a double range of interscapidars, one 

 of the oblique lower sides of eacli plate lesting upon tlie upper oblique edge of the inter- 

 costal, and the other upon tlie costal plate ; arms unknown ; cohinin near the pelvis, 

 composed of thin joints, alternating at distant intervals with a tliir ker one ; edges of the 

 plates of the column with slight longitudinal ridges or strias. 



This species has the same structure as the iS. nodosus, but the form of the body and plates 

 is quite different; the joints of the column are not nodulose, but longitudinally striated, 

 differing in an essential manner from the other species with which it is generically identical. 



This specimen was discovered after the descriptions of the above species had been 

 printed, but is added to the plate, which had not been completed. 



Fig. 4 a. The body of this species, with a small part of the cohmiii attached. 



Fig. 4 A. A portion of the column enlarged. 



Fig. 4 c. An enlarged figure, showing the structure and arrangement of the plates. 



Position and locality.- In the intercalated shaly layers in the Trenton limestone at 

 Middleville. 



121. 1. GRAPTOLITES AMPLEXICAULE (p. 79). 



It is quite possible that this species will prove identical with G. pristis, or some other 

 one of the higher slates ; though in the limestone, when not compressed, it presents a 

 different aspect. 



123. 1. POTER'IOCRINUS ALTERNATUS ( pag. 83, pi. 28, figs. 1 a -/). 



This species may perhaps be a Cyathocrinus ; but the form of the plates is the same 

 as in P. gracilii-, which presents all the generic characters given by Miller. It may be 

 doubtful even whether the distinction between Poteriocrinus and Cyathocrinus is always 

 conspicuous or readily decided. 



379. 3. NUCULA? DONACIFORMIS. 



Pi.. XXXllI'. Figs. 3 a,b. 



Ovate-cuneate, the anterior side short and rounded, the posterior side extended, nar- 

 rowing and compressed laterally, inflated towards the umbones, which are prominent and 



