259 



DISTRIBUTION AND GENERAL NOTES ON THE SPECIES 



PETROMYZONIDAE 

 A specimen of Geotria australis Gray was obtained by Dr Hamilton in the Falkland Islands, but none 

 was taken during the trawling surveys. Possibly the marine phase of the life history does not extend 

 far beyond the littoral zone, but the general distribution of the species appears to be circumpolar in 

 sub-Antarctic waters, and even extends to subtropical waters in AustraUa. 



MYXINIDAE 



Three 'good' species of the genus Myxine were recognized by Norman (1937, pp. 4-7) from the 

 Patagonian region. One of these, M. tridentigera Garman, was not obtained by the Discovery Com- 

 mittee's ships. It is known only from the unique holotype from Magellanes. Four specimens of 

 M affinis Gunther were taken at St. WS582 in a dip-net, but none from the area of the trawlmg 

 surveys The remaining species, M. australis Jenyns, seems to have a much wider distribution. It is 

 common at the Falkland Islands, where specimens have been collected by Bennett and HamiUon, on 

 both coasts of South America and particularly in the Magellan channels. A specimen has also been 

 collected by Hamilton at the South Shetlands, a fact of exceptional interest, as I am not aware of any 

 other record of a cyclostome being taken south of the Antarctic convergence. Details of our obser- 

 vations on the distribution of this species are : 



I : in ' Trawl + accessory nets ' 



Mean depth 



Station 

 WS763I 

 WS789 

 WS792 A 



WS797C 



Myxine australis Jenyns. 

 Mean depth 



m. 

 84 



94 

 104 

 112 



Numbers 



I 



7 



I 



10 



Station 

 WS812 I 

 WS833 

 WS834 



Numbers 



Station 

 Port Stanley (J. E. H.) 

 Salvador waters (A. G. B.) 

 Port Stanley (A. G. B.) 

 WS835 

 WS836 



II: in 'Other gear' 

 Mean depth Numbers 



m. 



? 



? 

 ? 



15 

 64 



etc. 

 I 

 I 

 I 



6 in BTS 

 I in BTS 



Station 

 WS856 



WS871 

 WS873 

 WS878 



S3 

 34 

 32 



Mean depth 



m. 



104 



338 



93 (-°) 

 121 (-0) 



Numbers 



etc. 

 I in BTS 

 I in BTS 

 I inNR 

 5 inNR 



Thus although the majority of specimens were captured in shallow inshore waters the species has 

 been taken below 300 m., and at four of the remaining fifteen stations the depths slightly exceeded 

 100 m It also extended much farther north on the east coast than the other species, a considerable 

 concentration being found off the Golfo san Jorge. The other records are mostly grouped much 

 farther south, off the mouth of Magellan Straits and the north-east coast of Tierra del Fuego There 

 is no obvious reason for such a discontinuous distribution, but the gear used is obviously far from 

 efficient for the capture of such slender organisms, and as it was not obtained in l^'-f ^.^^ers any- 

 where, insufficient sampling is quite possibly the sole cause. Apart from the probability that M 

 australis will be found to attack useful fish, especially those that come well inshore, it is of no potential 

 economic significance. LAMNIDAE 



Cetorhinus maxirmu (Gunner). No basking sharks were seen or captured by our ships within the 

 trawling area. Norman (1937, P- V) gives the details known concerning one washed up in East Falkland 

 and quotes HamiUon's observations on another seen off Cape Dolfin m 1936. He notes that it may 

 prove to be distinct from the common species of the northern hemisphere. 



1 See pp. 250-1 for distinction between ' northern', ' intermediate', and ' southern ' regions. 



