SURVEY OF STRUCTURE 



29 



A well-developed swimbladder is found in the genera Argentina, Glossanodon, Microstoma and 

 Nansenia (Cohen, 1958; Fange, 1958, and personal observation). Fange's description of the swim- 

 bladder of Argentina silus shows that micro-retia are also present in another deep-sea salmonoid and 

 that the system is highly developed. I have also found an extensive development of micro-retia in 

 Microstoma and Nansenia. However, as these four genera appear to consist of benthic fishes they are 

 not considered here. Further discussion may be found in the section on pages 53-54. 



The swimbladders of the two species of Opisthoproctus and Winteria telescopa were not sufficiently 

 well preserved to trace the resorbent capillary network. However, it is likely to be found at the 

 posterior end of the sac. This is certainly true of Argentina and Microstoma, in which this part is thin 

 walled and carries a capillary bed (see also pp. 79-80). 



Text-fig. 14. Swimbladders of Winteria telescopa (a and b) and Opisthoproctus soleatus (d), seen from below. In (c) part 

 of a micro-rete of Winteria is seen and in (e) two micro-retia of Opisthoproctus grimaldii, which supply patches of gas-gland. 

 gg, gas-gland ;int, intestine; Iv, liver; mrm, micro-rete mirabile ; oy, ovary; ra, retial artery; rv, retial vein; sb, swimbladder; 

 st, stomach, (a, X3"5; b, xi2"5; c . x °o; D, xio; E, x 60.) 



Family Bathylagidae 

 In his synopsis of this family, Chapman (1943) recorded that the swimbladder is completely absent. 

 Beebe (1933), who examined the internal organs of Bathylagns benedicti and B. glacialis, made no 

 mention of this organ, while I could find no trace of it in B. antarcticus and B. argyrogaster. 



