240 
FISHES 
CHAP. 
articulated to each of its outer extremities the basal cartilage 
Ira. 142.—The left half of the pelvic 
girdle and the right pelvic fin of 
meta, Metapterygium ; 
(From Parker and 
Chiloscyllum. 
pelv, pelvic girdle. 
Haswell.) 
with each other. 
as Ss 
as 
DER 
a secondary girdle (Fig. 143). 
— 
(metapterygium) of the pelvic 
fin. Sometimes there is a rudi- 
ment of a dorsally-directed “ iliac ” 
process at each extremity of the 
girdle, but in no Fish do these 
processes ever acquire a dorsal 
connexion with the vertebral 
column. In the Holocephali the 
iliac processes are better developed 
than in any other Fishes, but 
ventrally the lateral halves of the 
girdle are united by ligament 
alone. In the Teleostomi im- 
portant differences are observable 
in both girdles. The primary 
cartilaginous pectoral girdle. now 
consists of distinct lateral halves 
which have no ventral connexion 
In addition, there is developed on the outer 
surface of each half a series of membrane bones, which form 
Fig. 143.—Left half of 
the pectoral girdle of 
a Trout (Salmo fario), 
seen from the inner 
surface. CZ, Clavicle 
(cleithrum) ; COR, 
coracoid; D.F.R, 
dermal fin-rays; 
MS.COR, meso-cora- 
cold) iC we Gis 
post-clavicles; 
PTG.1, proximal; 
ptg.2, distal pterygio- 
phores: PPG 
post-temporal ; S.CZ, 
supra-clavicle ; SCP, 
seapula, (From 
Parker and Haswell. ) 
- scpe/2—— 
PYG2 PTC. 
From above downward the series 
includes a supraclavicle and a cleithrum (clavicle of Teleosts) 
which are always present, and to these may be added in the 
