284 PALEONTOLOGY OF NEW-YORK. 
129. 1. TENTACULITES FLEXUOSA. 
Pu. LXXVIII. Figs. 2 a, b. 
Reference pag. 92, pl. 39, fig. 6 of this report. 
Tentaculites. Emmons, Geol. Report, 1842, pag. 404, fig. 6. 
Compare Cornulites serpularius, ScutorHEiM, Murcuison, Sil. System, pag. 627, pl. 26, figs. 5-8. 
This species is equally as abundant in the rocks of the Hudson-river group as in the 
Trenton limestone. In the latter it often attains a greater length, and is nearly straight or 
simply curved. The flexuous character, therefore, may not be constant or essential in 
distinguishing the species, though I have not seen perfectly straight specimens. In the 
shales and ferruginous shaly sandstones of the Hudson-river group, the moulds only of this 
species are found, and the fine longitudinal strie are rarely well preserved. It is distinct 
from either of the species described by Mr. Murcutson, from the Caradoc sandstone.* 
Fig. 2 a. Fragment of the stone with several specimens a, a, a, associated with corals, shells, etc. 
Fig. 2 b. A specimen enlarged, showing the longitudinal striz. 
Position and locality. In the middle and higher parts of the Hudson-river group at 
Turin, Boonville, Loraine, Pulaski, and other places in New-York ; at Cincinnati ( Ohio ), 
Maysville (Kentucky), and Madison ( Indiana). 
NOTE TO THE _CRINOIDEA. 
Since this volume will be published without the elementary portion, which is in pre- 
paration, and will form a part of the next volume, the following explanations are given of 
the signs used in designating the structural arrangement of these animals. Those only 
are given which are used in the plates of this volume. 
B. Base of attachment. M. The hand. 
E. Pelvis. N. The fingers. 
F. Costal plate or joint. Q. Pectoral plates. 
G. Intercostal plate or joint. R. Capital plates. 
H. Scapular plate. = Cuneiform arm-joint. 
I. Interscapular plate. a. First. 
J. Irregular interscapular plate. b. Second. 
K. Arms. d. Joint, as =, first costal ; =, second costal, ete. 
L. Cuneiform joint. =, arm-joints. 
*In the description of this species, I had overlooked the analogy in its mode of growth to that of the Cornulites 
serpularius, so fully illustrated by Mr. Murcuison. The structure, however, is quite different, being annulated by 
sharp equal ridges, and not composed of sections of different sizes, one proceeding from the other. The apparently 
septate character, shown in a single large individual in the Trenton limestone, may indicate a structure incompatible 
with the true Tenracutrres. Its geological position is below that of the Cornulites serpularius ; and should further 
examination and comparison prove it to be generically allied to that one, it will form a distinct species. — 
. 
