31872. ] 331 {Cope. 
Protosphyrena,* with two species, P. ferox and P. striata. The latter 
much resembles a Sawrocephalus, having equal teeth ; while the former 
probably includes several species, and possibly genera. The teeth first 
referred to it resemble those of P. striata, while others resemble those of 
Portheus. An examination of the figures of the mandibles of the last in 
Dixon’s work, show that the large and small teeth occupy different areas, 
separated by grooves ina manner quite distinct from anything seen in 
Portheus ; but, should it prove identical, it can scarcely be regarded as 
typical of Protosphyrena, which name, moreover, has never been accom- 
panied by the necessary description. 
Dr. Leidy applied the name of Xiphactinus to a genus indicated by a 
spine, in some degree like those regarded above as ventrals of Sauro- 
dontide. It is quite distinct from those assigned to Portheus and Ichthy- 
odectes, and may belong to Saurocephalus, as already suggested, or to 
another genus. 
PORTHEUS. Cope. 
(Proceed. Amer. Philos. Soc., 1884, po 178.) 
Teeth subcylindric, without serrate cutting edges, occupying the pre- 
maxillary, maxillary and dentary bones. Sizes irregular, the premaxil- 
lary, medium maxillary and anterior dentary teeth much enlarged. No 
foramina on inner face of jaws. Teeth on the premaxillary reduced in 
number. Opercular and preopercular bones very thin. Cranial bones 
not sculptured. 
The fishes of this genus were rapacious, and, so far as known, of large 
‘Size. They constitute the most formidable type of Physostomous fishes 
known. Three species are known to the writer, one from teeth only, 
from the Miocene of North Carolina, but not certainly known to be an 
intrusive cretaceous fossil; and two from Kansas. The latter are rep- 
resented by more or less numerous fragments of eleven individuals, 
three of which possess large portions of the cranium, one almost entirely 
‘complete. Two of the remainder embrace jaws, and one a large part of 
the vertebral column, with segmented rays. In one, these rays were 
found with the cutting compound ray above described ; while the simple 
flat ventral rays occur with several specimens. In none have any traces 
of symmetrical spinous rays been found, nor strong interneurals capable 
of supporting such. In none of the more perfect specimens with crania 
have the segmented always been found, but the fossil of P. thaumas, 
where they occur, is represented by a vertebral column and its append- 
ages, which do not differ appreciably from those of P. molossus. 
In the cranium of this genus, there is a well-marked supraorbital rim. 
Each opisthotic forms a prominent angle, directed posteriorly on each 
‘Side of the exoccipital. The parasphenoid is a stout and narrow bone, 
deeply emarginate behind, for the passage of the muscular canal. It has 
a transverse expansion in front of the base of the prootic, which rests on 
4 backward continuation of the same. This expansion is pierced behind 
* Trans. Amer. Philos. Soc., 1856, 
