SURVEY OF STRUCTURE 47 



Melamphaes unicornis Gilbert (Text-fig. 28 E, f) 

 St. 3484. 39° 55' N -. 2 °° 01' W., 1. x. 56, IKMT, 75o(-o) m. (estimated). Standard length 51 mm. (6-5 x 2-5 mm.). 



The swimbladder of this melamphaid, which was quite relaxed, lies above the posterior half of 

 the stomach. 



Blood-vessels running down from the roof of the body-cavity enter the swimbladder roof at the 

 posterior end, where they supply the oval, which was completely closed. 



The single rete mirabile is about 3 mm. in total length. Since the sac is much contracted the rete 

 may well have been displaced forward from its natural position. In this swimbladder it originates 

 in a median lateral position and runs forward and across the floor of the sac, then turning backward 

 to the gas-gland, which is indented along its posterior edge. 



Melamphaes mizolepis (Giinther) (Text-fig. 28b-d) 



St. 288, oo°56'S., i4°o8-5'W., 21. viii. 27, YFT, 25o(-o) m. B.M. Reg. no. 1930.1.12. 1031-40. Standard 

 lengths of two individuals examined 15 and 37 mm. 



In the smaller of the two fishes dissected a small spherical swimbladder was discovered over the 

 anterior part of the stomach. It measured 0-4 mm. in diameter. The rete mirabile runs forward to 

 enter the posterior part of the swimbladder roof and then turns sharply downward to follow the 

 outline of the organ as far as the front part, where it joins the gas-gland. This is a compact spherical 

 structure almost filling the lumen. 



The posterior tip of the rete appeared to be closely bound to the stomach. Actually two branches 

 from the blood-vessels running over the stomach enter the rete. 



The structure of the swimbladder in the larger fish was very similar. The diameter was o-8 mm. 

 In both individuals it is obvious that the swimbladder is little more than a regressed organ. 



Melamphaes cristiceps Gilbert 



St - i°i. 33° 5°' to 34° 1 3' S., i6°04' to i5°4o/E., 15. x. 26, N 450 H, 1310-1410111. B.M. Reg. no. 1930.1.12. 

 1006-8. Standard length offish 80 mm. 



A small swimbladder was found behind the stomach and just in front of the ovaries. It measured 

 3-5 mm. in length. As in M. mizolepis, the rete mirabile runs round much of the swimbladder before 

 entering the gas-gland. It is evident that the swimbladder of this species is also regressed. 



A fully developed swimbladder is also found in Melamphaes macrocephalus, M. nigrofulvus, 

 M. opisthopterus ? M. nycterinas and M. cristiceps ? (Kanwisher and Ebeling, 1957). 



Family Anoplogastridae 



Anoplogaster longidens (Gill) (Text-fig. 28 a) 



St. 239, 46°56'S., 46°03'W., 2. vi. 27, N 450, i05o-i35o(-o) m. B.M. Reg. no. 1930.1.12. 974-6. Standard 

 length of fish 98 mm. 



In the medium-sized individual examined the swimbladder was found to be a small, almost 

 spherical sac overlying the foremost part of the stomach. Excluding the retia mirabilia, it measured 

 rather more than 3 mm. in length and about 2 mm. in greatest depth. The walls are thick and tough. 



Two retia mirabilia about 1 mm. in length enter the posterior end of the swimbladder, each running 

 to a lobe of the gas-gland. Together the two glandular lobes invest the floor and lateral walls of the sac. 



The swimbladder is surrounded by fatty tissue which is continued backwards for about 20 mm. 

 to taper off above the end of the stomach. The blood supply for the retia mirabilia came from vessels 

 within the fat body. 



