ACTINOPTERI. 151 



This species is only known to me from the above-described 

 type. Xo. 2264, Acad. Nat. Sci. Phila., from Monmouth County, 

 N. J. (Dr. P. D. Knieskern). Unfortunately it is without other 

 data and is accompanied by two small fragmentary bones, one 

 minutely denticulated, possibly belonging to the same animal? 

 This fossil is quite interesting as indicating the first instance of 

 the antiquity of Lepisosteus within our limits. 



Formation and locality. No formation or definite locality has. 

 been given for this species, which would, however, seem to be 

 Cretaceous? (Named for Dr. P. D. Knieskern, who collected 

 the type.) 



Order ISOSPONDYLI. 



THE ISOSPONDYLOUS FISHES. 



Anterior vertebrae simple, unmodified, without auditory ossi- 

 cles. Symplectic present. Opercles distinct. Pharyngeal bones 

 simple above and below, lower not falciform. Jaw bones de- 

 veloped. Maxillary broad, distinct from premaxillary, forms 

 part of upper jaw edge. No barbels. Shoulder-girdle well de- 

 veloped, connected with cranium by bony post-temporal. No 

 interclavicles. Mesocoracoid arch always well developed, as in 

 ganoids, forming bridge from hypercoracoid to hypocoracoid 

 Gills 4, slit after fourth. Air-vessel, if present, with pneumatic 

 duct. Scales usually cycloid, sometimes ctenoid, occasionally 

 absent. No developed photophores. Dorsal and anal fins with- 

 out true spines. Adipose fin present or absent. Ventral fins ab- 

 dominal, sometimes wanting. 



A large group, containing about 54 families, some of which 

 show characters analogous in some of the ganoid Halecomorphi, 

 seemingly pointing to a possible line of descent. The present 

 order is a very large group, containing a vast number of marine, 

 soft-rayed fishes among living forms, though the fossils are 

 much less numerous. 



Family RAPHIOSAURIDtE. 



Dentition with short stout fangs occupying alveoli, of which 

 inner side and part of anterior posterior walls incomplete Teeth 



