I2 DISCOVERY REPORTS 



lobe supplied. The forward and lateral edges of the two smaller lobes have a vein running round 

 them, while the whole of the inner edges and about half of the outer edges of the larger lobes are 

 similarly supplied with a venous system. The periglandular veins give off venules that divide again 

 and again to form a dense capillary system, which is eventually linked with that formed by the branch 

 of the retial artery. (The arteries to the lobes play no part in this capillary formation and do not 

 branch until they have entered the gland.) The pattern of arterioles and venules can best be appre- 

 ciated by reference to Text-fig. 3 a. 



This extensive capillary complex forms the resorptive region whereby gases diffuse out of the 

 swimbladder and into the blood stream. 



B 



Text-fig. 3. Swimbladder of Maurolicus muelleri: (a) viewed ventrally, and (b) shown in position in the fish. Veins shown 

 black, arteries white. Note the two small and two large lobes of the gas-gland, av, artery-vein pair to gas-gland ; bpr, by- 

 pass branch of retial artery ; en, resorbent capillary network ; gg, gas-gland ; ra, retial artery ; rv, retial vein ; rm, rete mirabile, 

 (Swimbladder, x 30; fish, x 2.) 



