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POPULAR SCIENCE MONTHLY 



10. Gasteropelecus stellatus Kner, an Extremely Swell Gharacin. This is connected by 

 many intermediate forma with normal-shaped species. 



interesting Diplomyste, which is found on the northern border of 

 Patagonia, but is not a derivative of the tropical American fauna. It 

 is a relict of the original catfishes, in which the maxillary is still func- 

 tional as a tooth bearer. Here belongs also Nematogenys, a catfish 

 related to Pygidium. Like the members of group 2, these species are 

 confined to the northern fringe of the Patagonian area. 



4. There remain unaccounted for the members of the Aplochitonidse, 

 Galaxiidae and Petromyzontida?, chiefly of southern Patagonia. 



Of the Aplochitonidae there are two genera, Aplocliiton, with an 

 undetermined number of species in the Patagonian region, and 

 Prototrodes, with three species, one in Queensland, one in South 

 Australia and one in New Zealand. 



Of the Galaxiida? there are two genera, Neochanna {apoda) from 

 New Zealand, where it frequently burrows in damp clay away from 

 water, and Gdlaxias, with about 30 species, from New Zealand, New 

 South Wales, South Australia, Tasmania, Cape of Good Hope, south- 

 ern South America and the Falkland Islands. The Petromyzontida? 

 are found in all temperate fresh waters and seas in both the northern 

 and southern hemispheres. 



The distribution of the two former families is of interest in con- 

 nection with the theory of a former antarctic continent connecting the 

 land masses in which they are found. In favor of a former land 

 connection it may be argued, and with justice, that while these species 

 descend to the sea, the probability that any pair of individuals should 

 migrate from Cape Horn to N~ew Zealand, or vice versa, is highly im- 

 probable. (This objection loses some weight if they spawn in the 

 sea, as is reported.) There are no intermediate places that might be 

 colonized and serve as new centers of distribution. It may further be 

 urged that these species could readily have been distributed to their pres- 

 ent homes by migration from stream to stream along a continuous coast 

 line or on a land-wave moving from one place to another. An obvious 

 objection comes from the paucity of the forms with this peculiar dis- 



