29 
Cope.] 338 {Jan. 5,. 
Enamel smooth, without sculpture; anterior cutting edge without 
crenations, more curved backwards than the posterior, which has but 
little curvature. Inward curvature slight. 
Lines. 
Diameter (anteroposterior) at middle crown .......... 0.2.06. 5 
ae transverse. ab Middle crown ese. euvig tind ives Ue 4 
se ae TOHAR UII os cs ENG oe gk, oe eee ae 3 
es AUGOTOMPOSHOTION NOAC TDS ss ive ek bone rede oe 2 
Discovered by Prof. C. Kerr, State Geologist of North Carolina, in the 
Miocene marl, Duplin Co., North Carolina, with Polygonodon rectus,. 
and Ischyrhiza antiqua, Leidy. 
ICHTHYODECTES. Cope. 
(Proceed. Amer. Philos. Soc., 1870, Nov. Hayden’s Geol. Survey, Wy- 
oming, ete., 1871, p. 421.) 
Teeth equal subcylindric, in a single row, sunk in deep alveoli. Pre- 
maxillaries short. No foramina at the bases of the teeth on the inner 
alveolar walls. Vertebree deeply grooved laterally. 
The species of this genus are, so far as known, smaller than those of 
the last ; and as their remains are more perishable than those, they form 
a less striking object among the fossils of Kansas. They are neverthe- 
less, very abundant, especially in species, five of which are now described. 
In originally describing this genus, the vertebrae were regarded as not 
grooved, in consequence of such vertebre having been discovered along 
with the bones and teeth of J. ctenodon. Further examination has satisfied 
me that this union is erroneous, and that the bones, if found together, 
were accidentally so. 
Spines similar to those of the Porthei, but presenting certain differ- 
ences, may be referred to this genus. The compound segmented spines 
cannot be ascribed to it, but the compound fulcrum-like spines are similar, 
though composed of fewer and stouter rods. Each of these, as it termi- 
nates at the cutting edge, give rise to a projection, giving it an obtusely 
and remotely serrate character. It is rugose with enamel deposit, and 
constitutes as effective a weapon of defense as that of Portheus. One, 
which is nearly perfect, contains fifteen pairs of rods, which expand at 
the base, as do the rays of a pectoral fin. Total length, M. .235; width, 
at base, .04; thickness beyond base, .006. 
The femoral bones have already been described. The maxillary is not 
contracted at the end for a supernumary bone, as in Portheus. 
The form of the inferior quadrate is like that of Portheus ; in I. anaides, 
the groove for the preoperculum extends low down, and the symplectic 
has a wider exposure on the outer face than in Portheus. 
In a series of vertebree similar to those of this genus, those included im 
the basis of the caudal fin are not more than three in number. 
