GEOGRAPHICAL DISTRIBUTION 19 



GEOGRAPHICAL DISTRIBUTION 



This very rich collection has considerably extended our knowledge of the geographical distribution of 

 most of the species represented in it. Although many of the species have been recorded from both 

 northern and southern hemispheres, there is no definite evidence of bipolarity. On the contrary, 

 a closer examination of the species, which had been regarded as common to the two hemispheres, has 

 proved in several instances that those from southern waters differ from those of northern waters so 

 consistently as to leave no doubt that they belong to different species. 



Hansen (1908, p. 100) suggested that as the specimens of Boreomysis scyphops G. O. Sars, which had 

 been recorded from off the coasts of Finmark, did not agree with specimens which had been recorded 

 under that name from the south-west of Australia, they should perhaps be referred to a different 

 species. W. M. Tattersall (1951, p. 46), when studying the rich material of the United States National 

 Museum, was able to confirm Hansen's observations and separated the southern specimens under the 

 name B. inermis. He found that although this new species differed from the north European 

 B. scyphops, it had a very wide distribution in the Pacific and occurred at many stations along the west 

 coast of California and northward to the Behring Sea in the east, and in the Sea of Okhotsk in the 

 north-west. The previous records were all from far south in the southern hemisphere, from the 

 Weddell Sea, from near the Crozet Islands and from two stations to the south-west of Australia. 

 The record in the Discovery collection is from South Georgia. B. inermis is bathypelagic and in all 

 probability has a very wide distribution in the deep waters of the world. I think that the fact that it 

 occurs so far north in the Pacific and so far south in the southern hemisphere points, not so much to 

 an exhibition of bipolarity, but rather to the possibility that further exploration of the intermediate 

 localities will reveal that it is present in the deeper waters. Its occurrence near South Georgia, so far 

 north of its previous record from the Weddell Sea, supports this suggestion. 



Fage (1942, pp. 7-39) thoroughly revised all the literature and records concerning Lophogaster 

 typicus — a species which was originally recorded from North European waters and which has since 

 been recorded from such widely separated localities that it has been regarded as having a world-wide 

 distribution. He found certain well-defined differences whereby these animals could be separated 

 into four distinct species, and he noted further that these could be correlated with their geographical 

 distribution. One of his new species, L. challengeri, which previously was only known from off Cape 

 Town, is represented in the present collection. It was taken by the ships of the Discovery Investiga- 

 tions at several stations around the south coast of South Africa and on three occasions off Cape Lopez. 

 This extension northward of its known range may possibly be due to the influence of the Benguela 

 Current, but until all the material recorded under the name of L. typicus has been re-examined, it is 

 impossible to be sure that specimens of L. challengeri may not have been recorded from other localities 

 as typicus. A careful comparison of the Discovery specimens with those of L. typicus from the west 

 of Ireland fully bears out the observations made by Fage, and I accept L. challengeri as a valid species 

 which is distinct from the northern L. typicus. 



Zimmer (1914, p. 392) founded the species Longithorax capensis on a single adult male from South 

 African waters. Nouvel (1943, p. 75) doubtfully referred a damaged immature specimen from deep 

 water off the Azores to this species and W. M. Tattersall (1951, p. 121) referred specimens from the 

 Bermudas to the same species. Both authors recorded certain differences between their specimens and 

 Zimmer's description of the type, but attributed these, in the one case to the immaturity and damaged 

 condition of the specimens, and in the other to immaturity and difference in sex. A close examination 

 of the records and figures, together with a study of the present material, has convinced me that 

 Nouvel's specimen from the Azores and Tattersall 's from the Bermudas belong to the same species 



3-2 



