144 



FISHES. 



or three partitions situated behind one another; they may 

 consist of two lateral partitions, assuming a horseshoe-like form, 

 or they may be a single sac with a pair of simple or bifid 



Fig.61.— Air-bladderof 

 Otolitliiis sp. 



Fig. 62. — Vertical section through ab- 

 dominal cavity of CoUichthys lucida. 

 b, air-bladder ; I, liver ; s, stomach ; 

 epp and ipp, external and internal 

 laminae of peritonenm parietale ; epv 

 and yju, external and internal laminae 

 of peritoneum viscerale ; dv, dorsal 

 air-vessels ; vv, ventral air-vessels. 



processes in front or behind (Fig. 61). The families of Scice- 

 nidce and Poli/nemidoi possess air-bladders with a most 

 extraordinary development of appendages rising from each 

 side of the air-bladder. In the Scisenoid (Fig. 63) fifty-two 

 branches issue from each side, each branch being bifurcate 

 and bearing smaller appendages. In Pogonias cliromis (Fig. 

 64) the sides of the anterior half is provided with irregular 

 broad-fringed appendages, the hindmost of which communi- 

 cates by a narrow duct with the posterior extremity of the 

 air-bladder. In CoUichthys lucida (Fig. 62) twenty-five ap- 

 pendages issue from each side ; the anterior ones are directed 

 towards the front, but the lateral assume a more posterior 



