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EASTMAN: CARBONIFEROUS FISHES FROM THE CENTRAL WEST. 207 
Physonemus hamus-piscatorius, sp. nov. 
(Plate 5, Figs. 45, 46.) 
Type. — Exserted portions of spines; Museum of Comparative Zoology. 
Small hook-shaped spines, circular in cross-section, traversed by a small 
central pulp-cavity, and maintaining a nearly uniform diameter for the greater 
part of their length. External surface smooth or slightly roughened but not 
tuberculated, and no denticles present on either side. Inserted portion not 
observed. 
The peculiar unciform spines shown in Plate 5, Figs. 45 and 46, from the 
Kinderhook limestone of Iowa, are the only examples at present known of this 
species. Both specimens are slightly abraded and afford no clue as to the 
nature of the inserted portion. The larger one is also fractured longitudinally 
for a considerable distance in such manner as to expose the tubular pulp- 
cavity, which in contrast to most species occupies a central position. The 
most striking differences displayed by the present form, however, are its cir- 
cular cross-section and almost total absence of ornamentation. A small spine 
from the St. Louis limestone described by Messrs. St. John and Worthen as 
Physonemus falcatus, but which is probably the young of P. arcuatus, ap- 
proaches the present form in its general outline, but differs notably in cross- 
section and other features. There is no reason to suppose that these spines 
are abnormally recurved, but on the contrary they may be looked upon as at 
once the most primitive, as they are also the earliest known representatives of 
Physonemus. 
Formation and Locality. — Kinderhook limestone; Burlington, Iowa. 
Physonemus pandatus, sp. nov. 
(Plate 5, Fig. 44.) 
Type. — Complete spine ; Museum of Comparative Zodlogy. 
Small, narrow, laterally compressed spines, the exserted portion erect and 
scarcely tapering for two thirds of its length, then becoming suddenly bent, 
more or less at right angles, but not decurved. External surface apparently 
unornamented, and denticles absent along the concave margin. 
The unique example upon which this species is founded exhibits the whole 
of the exserted portion, and is broken off at the expanded base, the inference 
being that it was buried only to a slight extent in the integument. It is dis- 
tinguished from the preceding species principally by its great lateral com- 
pression, and in its abrupt flexure without being curved downward toward the 
distal extremity. No traces are to be observed of superficial ornamentation, 
nor of denticles along the concave margin. This species, like the last, may be 
looked upon as a primitive forerunner of the group typified by P. arcuatus, 
immediately to be considered. 
Formation and Locality. — Kinderhook limestone ; Burlington, Iowa. 
