FOSSIL FISHES. af 
On the following pages, so far as I have been able, I have enumerated 
and defined all the species of the genus which have come under my obser- 
vation. Ideem it necessary to say, however, that future observations will 
probably diminish rather than increase the number of forms in which the 
differences should be given specific value. For example, J. alatus may 
prove to be only a variety of /. lineatus and I. modestus a phase of I. elegans; 
but with marked differences and without connecting links, so far as yet ob- 
served, it has seemed to me hardly justifiable without further evidence of 
identity to unite them under a common name. 
IscHyprerus ovatus W. C. R. 
Pleehiea 
Palwoniscus ovatus W. C. R., Am. Jour. Sci., vol. 41, 1841, p. 26. 
The only published description of this species is that cited above. It 
reads as follows: 
> 
Paleoniscus ovatus W. C. R.—Wide or round-shaped Palzoniscus. This spe- 
cies is shorter than P. Agassizii, and exceeds all the known American species in the 
comparative width or roundness of its form, and is also remarkable for the large size 
of its scales. It is of rare occurrence, and, owing probably to its great thickness, is 
seldom obtained in perfect form. This fossil also exhibits the spine-like erections of 
the dorsal scales which have been noticed above. 
Found at Westfield and Middlefield, Conn.; Sunderland, Mass., and Boonton, N. J. 
In the manuscript report of Mr. J. H. Redfield the following notes on 
this species appear : 
Fish ovate; head rather small and narrow; body widening rapidly from the head 
to the dorsal and ventral fins, expanding as far as the ventral fins, from which point 
the form gradually narrows to the pedicel of the tail. Seales large, anterior ones con- 
centrically striate, those of the dorsal ridge pointed and elevated as in P. tenwiceps; 
pectoral fins small, comparatively slender; ventrals small; dorsal large, rays strong; 
anal not well observed. This is the broadest and most ovate species of Palwoniscus 
that is known, and perhaps ought to be referred to a separate genus. In the size of 
the scales it resembles P. Agassizii, but its form will readily distinguish if. 
In the collections made at Turner’s Falls, Mass.,,and Boonton, N. J., I 
find a large species of Ischypterus, which agrees very well with the descrip- 
tions given above. The fish reaches a length of from ten to twelve inches, 
is ovoid in form, with a breadth at the dorsal fin of from four to five inches; 
