i 4 6 DISCOVERY REPORTS 



Tachysiims barbus (Lacepede), 35°-52° S. 

 Syngnathus acicularis, Jenyns, 35°-52° S. 

 Hippocampus punctulatus, Guichenot, 35°-43° 30' S. 

 Pinguipcs fasciatus, Jenyns, 35°-43°S. 

 Paralichthys brasiliensis (Ranzani), 35°-44° S. 

 Paralichthys patagonicus (Jordan and Goss), 37°-44° S. 

 Oncopterus darwini, Steindachner, 35°-44° S. 



NOTES ON THE FISH FAUNA 



The number of species recorded from the Patagonian region as here delimited is 128, 

 and of these 85 (about 65 per cent) were obtained by the Discovery Committee's ships. 

 A study of the list given above shows that, of the 128 species, 67 (52 per cent) are 

 apparently confined to the region, although it must be admitted that careful collecting 

 on the little-known coastal region of Argentina between the mouth of the Rio Plata 

 and the San Jose Peninsula would probably greatly increase the list of species which 

 extend northwards on this coast. A further 39 species are known to extend outside the 

 region along the coasts of Chile or Argentina, but do not occur elsewhere, so that no 

 less than 106 species (about 83 per cent) are inhabitants of the temperate and sub- 

 Antarctic coasts of South America. Of the remaining 22 species, 7 occur also in 

 Australia and New Zealand, 2 in New Zealand only, and 4 in South Africa. Only 

 3 species (Muraenolepis microps, Dissostichus eleginoides, Harpagifer bispinis) are found 

 also in South Georgia or in Graham Land. 



Leaving out of account the more widely distributed and often semi-oceanic fishes 

 such as Cetorhinus, Trachurus, Gasterochisma, and the deep-water Sharks of the family 

 Squalidae, the fish fauna of the Patagonian region may be roughly grouped into three 

 categories. These are : 



(1) Argentine or Chilean forms. 



(2) More or less cosmopolitan genera with representatives in both the Northern and 

 Southern Hemispheres. 



(3) Forms that are peculiar to the sub-Antarctic and Antarctic Zones (e.g. Noto- 

 theniidae, Zoarcidae). 



Characteristic genera in the second category are: Myxine, Squalas, Raja, Clupea, 

 Merluccias and Micromesistias. It is of interest to note that some of the species of these 

 genera can be paired off, as it were, with related species in the Northern Hemisphere, 

 sometimes well separated, sometimes so closely related that it is a matter of difficulty 

 to separate the two forms. Such pairs are : Myxine australis and M. glutinosa, Squalus 

 lebruni and S. acanthias, Raja flavirostris and R. batis, Raja doello-juradoi and R. radiata, 

 Clupea fuegensis and C. harengus, Clupea arcuata and C. sprattus, Merluccius hubbsi and 

 M. merluccius, Micromesistias australis and M. poutassou. The close relationship of some 

 of these pairs of species suggests the possibility of some fairly recent interchange 

 between the faunas of the North Temperate and South Temperate Zones, and, as 

 Regan 1 has pointed out when discussing the geographical distribution of the genus 



1 1916, Ann. Mag. Nat. Hist. (8) xvm, p. 15. 



