i894. SCORPIONS. 361 



divide the Neotropical Region into sub-regions. In a general way, 

 however, the northern parts of the area seem to be characterised by 

 the presence of Chactidae, and the southern by the presence of 

 Bothriuridas ; and it is interesting to note that both of these groups 

 are absent from the West Indies. There are, too, some further 

 points of interest connected with these islands. For instance, the 

 species known from the larger islands — i.e., Cuba, Jamaica, Hayti, 

 and Porto Rico — are, for the most part, also found on the mainland 

 of Central or South America ; while the species that have been 

 obtained in the smaller islands to the south-east — e.g., Montserrat, 

 St. Lucia, St. Vincent, and Grenada — are peculiar forms of the 

 Central and South American genera Tityus and Diplocejttrus. 



Some of the facts connected with the distribution of Scorpions 

 set forth in the preceding paragraphs ofifer interesting points for 

 further discussion. 



It is to be observed, in the first place, that arms of the sea 

 constitute barriers which these animals cannot pass; yet, although 

 their means of dispersal are very limited, the antiquity of the group 

 is so great that it has succeeded in distributing itself over all 

 the contiguous land areas of the globe. In fact, as we have seen, 

 these animals have been met with in all parts of the continents which 

 have been explored, with the exception of the colder parts of the 

 Northern Hemisphere, and in all continental islands with the single 

 exception of New Zealand. But we know that in pre-Glacial Ter- 

 tiary times they extended in Europe as far to the north as what is 

 now the southern shore of the Baltic ; and there cannot be much 

 doubt, one would think, that their absence at the present day from 

 all that area of the Northern Hemisphere which lies north of the 45th 

 parallel of latitude is to be attributed to the recent glaciation of this 

 part of the world. 



But their absence from New Zealand is not to be so easily 

 explained away. It is clear, however, that we have to account for 

 the fact upon one of two hypotheses, namely, that they have never 

 succeeded in reaching the country in question, or that they have been 

 exterminated since arriving there. 



The first hypothesis, however, seems hardly likely to be the true 

 one, if there has ever been an uninterrupted and long-continued land- 

 connection between New Zealand and the south-eastern parts of Asia 

 by way of Australia or Austro-Malaya. But if, on the other hand, 

 the connecting land was composed merely of islands, the intervening 

 seas would probably have afforded an effectual barrier to their 

 migration. 



With regard to the hypothesis of extermination, it may be said 

 that, so far as is known, there is nothing in the physical conditions of 

 New Zealand antagonistic to Scorpion life, and it must be left to the 



