Zoology. 125 
: . New inte From Lake Superior described by M. Agass 
The ne and valuable volume lately issued by Prof. renee 
his associates, ~aneetiai desestikts of numerous new forms of. 
sisal € now enumerate the preter. soa of fish described 
for the first time by Prof. Agassiz in this volume 
otpenser levis, Agass., p. 
afi 2 ‘Agass., Pp 271, (Plate ! rs Se. 1.) 
cheus, Agass., p. 276. 
Pimelodus "lie a p- 281. 
Percopsis, Agass., new genus. We quote the remarks of Prof. 
Agassiz in full pasacsed the very remarkable new genus of fish to - 
which he has assigned the name Percopsis. 
‘In order fully to understand and porieally to appreciate the charac- 
ters of this genus, and the interest grees in its discovery, it is neces- 
sary to remember various relations of the different types of the whole 
class, which however do not aaa generic distinctions, although 
they bear 7 ie the peculiarities of this new type. 
ent, as they belong to older geological deposits. The differences are 
even so great, that out of the four orders of this class, there are only 
~eoids and Ganoids. Moreover, the types are peculiar in all epochs. 
For instance, the sharks of former days, especially those of oo epochs, 
Tesemble solely that curious genus of Port Jackson, New and, the 
in the present creation, such as the gar-pike (Lepidosteus) . this con- 
tinent, are not less peculiar, and in connection with those ancient Pla- 
tion, each and ting their mounds of earth and sighing yepat xa 
neated ee te the fermentation of the vegetable matter, or of the 
rays, forma kind of natural hatching apparatus, from which the pike at Jength 
emerge fully feathered, and capable of iomabatiba life by their own unaided eff 
