118 TRANSACTIONS OF THE [pEc. 11, 
moreover, give an additional reason for emphasizing the most 
ancient origin of Dipnoan, Teleostome, and even Chimaeroid. 
The coprolite seems remarkably small in comparison with the 
total body width of the specimen; its striae are six in num- 
ber, and are somewhat irregularly disposed, the hindmost one 
notably furthest from its fellows. 
Myomeres are well shown in the fossil in the regions indicated 
(Fig. III., C. C. C.); a figure here given illustrates their coarse 
longitudinal striation (Fis. Wels): 
The especial interest which Cladoselache newberryi presents is 
in its Acanthodian features. It advances clearly from the 
known Cladodont forms along the line of specialization. It is 
in the first place a form of smaller size, of but somewhat more 
than half the length of /fyleri and less than one-third that 
of kepleri. Its pectoral fin is narrower and more acutely 
pointed, better adapted to a more specialized function; its 
radials becoming straighter and more compressed are strongly 
suggestive of the elements of the fin spine of Parexus. En- 
largement in size of the circum-orbital plates (with probable 
decrease in their number) is finally to be noted in its Acantho- 
dian bearing. 
Mr. Arthur Hollick made the following remarks on the paper: 
One part of Dr. Dean’s investigations throw an unexpected 
flood of light upon a matter in which I am much interested, and 
in regard to which there has always been a great diversity of 
opinion. 
I refer to certain peculiar screw-like fossils which have been 
described from time to time, both from this country and abroad, 
under the names Spiraxis, Spirangium, Paleoxyris, Palzo 
bromelia, Fayolia, ete. It may, perhaps, be remembered that 
Dr. Newberry described two species from the Chemung sand- 
stone, under the names Spiraxis major and Spiraxis Randalli, 
in the Annals of the Academy (Vol. III. (1855) 217-220, PL. 
XVIII.). His descriptions and figures and the type specimens 
upon which they were founded are here for comparison, and we 
can hardly doubt that they are identical with the coprolite 
figured by Dr. Dean from the intestine of the shark. 
These fossils have been referred by different investigators to 
Xyris, Bromelia, Chara, stems of alge, ete. Dr. Newberry did 
not venture any positive opinion as to their affinities, but men- 
tioned incidentally their possible reference to algee or sponges. 
Upon examining Dr. Dean’s drawing I was at once struck by 
the remarkable likeness between the coprolite and Spira.xis, and 
comparison of the specimens satisfied us both they represented 
similar fossils. 
