316 
PALAEONTOLOGY OF NEW-YORK. 
378. 2. SCHIZOCRINUS STRIATUS ( n. sp.) 
Pl. XXVIII. Figs. 4 a, b, 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 interscapulars, one 
of the oblique lower sides of each plate resting upon the upper oblique edge of the inter¬ 
costal, and the other upon the costal plate ; arms unknown ; column near the pelvis, 
composed of thin joints, alternating at distant intervals with a thicker one ; edges of the 
plates of the column with slight longitudinal ridges or striae. 
This species has the same structure as the S. 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 column attached. 
Fig. 4 b. 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. POTERIOCRINUS ALTERNATES ( pag. 83, pl. 28, figs. 1 a -/). 
This species may perhaps be a Cyathocrinus ; but the form of the plates is the same 
as in P. gracilis , which presents all the generic characters given by Miller. It may be 
doubtful even whether the distinction between Potcriocrinus and Cyathocrinus is always 
conspicuous or readily decided. 
379. 3. NUCULA'? DONACIFORMIS. 
Pl. XXXIII*. 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 
