360 



TELEOSTE1 



posterior chamber ; in OtoUthus a median chamber has paired lateral 

 prolongations (Fig. 349) ; in the Sciaenidae and Polyxeiridae in- 

 numerable branching diverticula are given off (Fig. 348) ; in 

 Callichthys the complication is still greater. The cavity of the air- 

 bladder is sometimes divided into compartments (Siluridae (p. 377)), 

 or small alveoli (Erythrinus). In the Herring (Fig. 383) a special 

 opening to the exterior is formed behind the anus (Weber) ; while 

 a communication is established with the right branchial cavity in 

 the physoclistous Caranx trachiurus (Moreau). The bladder is a 



Kio. 346. 



A and B, eye of AcawthUis vul&mii, Risso. B and C, eye of Salmosnlar, L. A and C, section 

 of eye vertical to surface, leaving the lens intact. 13 and D, inner view of the outer half of the 

 eyeball, showing the lens in position. 1, lens; 2, cut surface of retina ; 3, retina : 4, anterior 

 chamber or aqueous humour ; 5, posterior chamber or vitreous humour ; (>. pigment layer ; 7, 

 cut edge of sclerotic ; 8, iris ; 0, ora serrata ; 10, optic nerve ; 11, cornea ; 12, ventral accom- 

 modating muscle (ciliary process) ; 13, vascular ridge from choroid tissure ; 14, vascular process 

 (campanula Halleri). (Goodrich and Gradon.) 



hydrostatic organ, is never supplied direct from the aortic arches 

 (p. 226), and never functions quite as a lung ; but on its inner wall 

 are developed retia mirabilia, highly vascular patches, which secrete 

 the gases in the bladder (Hasse [199]). 



Caecal outgrowths towards the head and tail occur in a large 

 number of families (Berycidae, Siluridae, Clupeidae, etc.). A con- 

 nection between them and the ear is often established. In the 

 simpler cases a diverticulum on each side abuts against a 

 membranous fenestra of the periotic capsule, so that pressure or 

 vibrations can be communicated from the bladder to the perilymph 



