131 
PALAEONTOLOGY OF NEW-YORK. 
Gents Protaster ( Forbes). 
Memoirs of the Geological Survey of Great Britain, Decade I. 
“ Body circular, covered with squamiform plates : genital openings in 
“ the angles of junction of the arms beneath. 
“Arms simple, formed of alternating ossicula.” 
A large specimen of a similar fossil, preserved in the collections of the New-York 
Lyceum, was designated by the late Dr. Dekay as Euryale anmilatum ; but I am 
unable to find any description of it at this time. 
« 
Protaster forbesi (n. s.). 
Plate YII A. Fig. 8 - 10. 
Body circular, small, composed of squamiform plates. 
Arms live, large, subequidistant, composed of a single series of joints with 
a groove along the centre of the lower side, hearing jointed tentacles 
on the outer angles of the lower margins. 
The under surface of the disc and arms only is seen in the specimen : the scale- 
like plates are imbricated, and have granulate surfaces. The mouth is central. The 
buccal apparatus is composed of ten parts arranged in pairs; one-half of each pair 
springing from the base of each arm at their contiguous sides, and converging so as 
to form a falcate-lanceolate toothlike process from the sinuosities of the arms, and 
projecting deeply into the cavity of the mouth. These buccal processes are evidently 
articulated to the lateral margins of the first joints of the arms, like the succeeding 
tentacles, and differ little in appearance from those organs. The arm-plates are sub¬ 
quadrate, with concave bases and convex or pointed anterior margins, with a groove 
along the lower side, and connected together by a small cylindrical canal. The 
brachial plates, as seen from the lower side, are deeply indented at their base, and 
pointed above; so that when the arm was contracted, the plates closely interlocked, 
from the insertion of the pointed extremities into the hollow bases of the succeeding 
plate. Only four or five of the brachial ossicula of each arm are imbedded in the 
body; but from their comparatively large size, they have doubtless extended much 
beyond the disc. The outer lateral margins are indented near the extremities for the 
insertion of the tentacles, which are composed of two or more joints thickened at 
the articulating extremities. 
Fig. 8. The fossil, natural size. 
Fig. 9. Enlargement of the body and arms, with a restoration of the latter in outline 
beyond the limits of the body. 
Fig. 10. Enlargement of portions of an arm and tentacles, as seen from the lower side. 
