318 
PALAEONTOLOGY OF NEW-YORK. 
175. 8. ATRYPA CUSPIDATA (pag. 138, pi. 33*). 
This species, though differing from the original of A. extans , I am inclined to regard as 
identical with it, the differences indicated depending partly upon the accidental condition 
of the specimens. I have never been able to obtain perfect specimens, preserving the 
characters of A. extans represented in the single valves from which Mr. Conrad described 
the species. 
127. 1. ECHINO-ENCRINITES ANATIFORMIS (pag. 89, pi. 29). 
The structure cannot be entirely made out from the specimens in my possession. The 
pelvic plates are four, two of them truncated above, and one or both the others are pen¬ 
tagonal. A large part of the column is preserved in the specimens 4 a and 4 b. The 
specimen 4 d is crushed, and the column flattened, and appears wider than its proper 
proportion. In the specimen fig. 4 d ', the natural proportions are preserved. The lower part 
of the column, which is very small, and composed of joints twice or thrice as long as wide, 
is magnified in fig. 4 a+. This part of the column is not preserved in any of the specimens 
except fig. 4 a. 
128. 2. ASTERIAS MATUTINA (pag. 91, pi. 29). 
Prof. Agassiz has shown me that this species, though having the form of an Asterias, 
presents a generic difference, requiring another designation. 
This species, with several other species of asteroid-crinoids in the palaeozoic strata, will 
constitute a distinct genus, whenever their characters shall have been sufficiently studied. 
313. 1. THALEOPS (ILL.ENUS ) OVATUS ( p. 259). 
Pl. LXVII. Figs. 6 a, b, c (fig. 6 c added). 
Since this description was written, I have had an opportunity of examining a specimen 
from the collection of Mr. W. H. Pease, which is more perfect in some respects than the 
one previously described and figured. This individual is provided with a strong angular 
spine, projecting from each posterior angle of the buckler, nearly at right angles to the 
axis of the body. Spines of this character have sometimes been seen in the Trenton lime¬ 
stone, and in the Blue limestone of Cincinnati. The specimen described is from the southern 
part of Indiana, the precise locality unknown. 
354. 14. MODIOLOPSIS TERMINALIS (n. sp.). 
Pl. XXXIII*. Fig. 5. 
Reference Modiolopsis (species undetermined), p. 297. 
Since the description and figure of this species were completed, I have obtained a very 
perfect cast of the same, which is figured as above. The beaks appear to be terminal, or 
extending quite as far as the anterior margin of the shell. The form of the shell is similar 
to M. nasutus , but the position of the beaks readily distinguishes it from that species. 
