The Geographical Distribution of the Arachnida 

 of the Orders Pedipalpi and Solifugae. 



By R I. Pocock. 



Since the science of zoo-geography has hitherto been studied mainly 

 from the vertebrate standpoint, one of the most interesting develop- 

 ments of the science in the future will be to discover whether the 

 results obtained by a knowledge of the distribution of the orders of 

 terrestrial invertebrates contradict or coincide with those that have 

 been obtained by a study of the reptiles, birds, and mammals. More- 

 over, since it is generally admitted that the only means of mapping 

 the various geographical realms, regions, and provinces, on the basis of 

 an acquaintance with the dispersal of all land-species, is the publication 

 on the part of specialists of charts representing the range of the orders, 

 families, and genera with which they alone are familiar, it behoves all 

 systematic workers who are interested in this important branch of 

 zoology to contribute what they can to this desirable result. 



In the May number of Natural Science for 1894 1 briefly discussed 

 the geographical distribution of scorpions, and attempted to map out 

 the regions which the ascertained facts with regard to the range of the 

 families and genera of these Arachnida seemed to establish. In the 

 present paper I propose to deal in the same way with two other orders 

 of the class, namely, the Pedipalpi and Solifugae. Unfortunately, to 

 many of the readers of Natural Science these names will perhaps con- 

 vey no idea of the nature of the animals under discussion ; but since it 

 is impossible to enter at length into an explanation of their systematic 

 position, a very few words on this point must suffice. 



The term Pedipalpi is applied to a group of Arachnida which, 

 while possessing striking structural peculiarities of its own, lies in 

 many respects midway between scorpions and spiders. It is divisible 

 into two sub-groups ; the Uropygi or tail-bearing Pedipalps, in which 

 the last abdominal somite retains, in the form either of a many-jointed 

 feeler or of a one-jointed horny piece, a post-anal sclerite or telson, the 

 homologue of a scorpion's sting ; and the Amblypygi or tailless Pedi- 

 palps, in which this sclerite has disappeared. These two sub-groups, 

 the Uropygi and Amblypygi, are so very distinct that in the following 



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