605 



in Lophobranchs. But the physical and mechanical conditions existing 

 in the swim-bladders of the other species of this type are so different 

 from those found in the species which Baglioni investigated that it is 

 difficult to understand how his conclusions we apply to the group as 

 a whole. The physiology of the organ in the whole group of fishes in 



midl rd 



Fig. 6. Diagram of swim-bladder with oval, epi epithelial lining, inl inner 

 layer, midl middle layer, outl outer layer, phf peripheral fold of oval (radial section). 

 oval epithelium of oval, rd red gland, rt rete mirabile. 



Fig. 7. Section of red gland in the swim-bladder of Opsanus tau. cnt connective 

 tissue, cp capillary bundle, epi epithelium lining the swim-bladder, sbl cavity of the 

 swim-bladder. 



which this type of swim-bladder is found deserves special investigation 

 by experimental methods. 



The most highly specialized type of swim -bladder is shown in 

 Fig. 6. This consists of a closed, single - chambered organ, on the 



