= — = SR ‘ 4 an oe 
to: Bo ee ay. 
’ Pel. 0a et by 
. 2 alts. ge : 
2 get no. 
432 ae 
2 2 
contains the brain and shelters the ears—and the jaws and gill-skeleton. The 
shape and the position of the various bones entering into the cranium may be 
seen from fig. 3, A. and B. In many fishes the cranium is largely cartilaginous, 
Fig. 3 B.—Cranium AND ANTERIOR VERTEBRE 
Fig. 3 A.—CraNIUM AND ANTERIOR VERTEBRA 
OF CATFISH FROM ABOVE. 
M, mesethmoid ; pm, premaxilla; a, antorbital ; 
n, nasal; e, parethmoid ; fr, frontal; s, spheno- 
tic; p, pterotic; ep, epiotic; t, supraclavicle ; so, 
supraoccipital spine ; 4, transverse process of fourth 
vertebra, 
OF CaTFISH, FROM BELOW. 
Pm, premaxila; m, mesethmoid ; v, vomer; pa» 
parethmoid ; 0, orbitosphenoid; f, frontal; ps; 
parasphenoid ; a, alisphenoid ; pr, prootic ; h, arti- 
cular surface for .hyomandibular on sphen, and 
pterotics; b, basioccipital with exoccipitals on 
either side; s, supraclavicle; m, ‘‘malleus;” 4, 
5 and 6, transverse process of 4th, 5th and 6th 
vertebre. 
eristle or cartilage being only partly replaced by bones. In the Catfish, however, 
there is little of this left in the adult fish. Attention is called to the position of the 
vomer the teeth on which sometimes furnish easily accessible characters to the syste- 
matic zoologist. It is applied to the under surface of bones formed in cartilage, the 
foremost of which, the middle ethmoid, carries in front the premaxille, tooth- 
bearing plates which form a considerable part of the margin of the upper jaw on 
each side and which can in some fish be thrust out from their support or . 
“protracted.” The rest of the margin of the gape above is usually formed of the 
