1893.] DISTEIBUTION" OF BAETHWORMS. 737 



Before commenting upon the facts rendered apparent in this 

 list, it will be necessary to correct it in one or two parti- 

 culars. In the first place, it will be noticed that the genera 

 Laimhncus and Allolohopliora, and also, though to a less extent, 

 AUurus, are nearly world-wide in range. I believe that this ex- 

 tensive range is accidental, and due to the interference of man. 

 This opinion is based upon the foUoAving facts. In such countries 

 as Australia the presumably indigenous fauna {Cnjptodrilus, Mega- 

 scolides &c.) is met \x\t\x only at some distance from towns ; the 

 gardens of the latter contain Lumbricids only \ In no case is a 

 member of this family from any country outside the territories 

 covered by the Pal^earctie and Nearctic regions specifically different 

 from forms living wil:hiu those two regions. If the exotic Lumhri- 

 cidoi were indigenous to such countries as New Zealand and South 

 Amei'ica, it might be fairly expected that they would show at the 

 very least varietal differences ; but they do not. So, too, with the 

 few PericJuetldce found in Europe ; they are identical with exotic 

 forms, and have not been included in the above list. 



The same argument cannot perhaps be applied to the North- 

 American Continent ; although the majority of species belonging 

 to this family that occur there are the same as European forms, 

 there are a few which are peculiar. It seems to me to be exceed- 

 ingly possible that the same line of argument can be applied to the 

 genera Eudrilus and Pontoscolew. The latter genus has three 

 species; one of these, which was the earliest to be described, viz. 

 Pontoscolex corethrurus, is found in many widely separated parts of 

 the world. Individuals from Queensland show precisely the same 

 characters as others from British Guiana. Without stronger 

 proof than we have at present to the contrary, I should be dis- 

 posed to consider the genus to be American (Neotropical), and to 

 have been transferred accidentally to other countries. I may 

 mention that in gatherings of Earthworms which have been acci- 

 dentally brought to the Eoyal Grardens, Kew, in Wardian cases, 

 this species is about the commonest form. The same line of argu- 

 ment applies to Eadrilus eugenice ; but in this case I should look 

 upon tropical Africa as the real home of the species, common 

 though it is in tropical America. 



The above table, being, I hope, a complete list of the distribution 

 of the genera of Earthworms, does not bring out into I'elief the 

 characteristic features of the se /eral regions ; for instance, Perichaita 

 and Megascolex and also Periomjx are rare in tropical Africa. 

 Cryptodrilus is only known from the Neotropical region by one 

 species doubtfully refei'able to the genus. Taking those genera 

 which are abundant in species and in individuals and leaving aside 

 genera which are rare and only known by a single species, the 

 followng list of the Earthworm-faunas of Mr. Sclater's Eegions 

 may be drawn up : — 



PALiE.viicxic KBGiON. — Lumhricus, AUolobopJiora, AUurus, Orio- 

 driliis. 



Neaectic region. — Lumhricus, Allolohophora . 



^ I am indebted for thie interesting fact to Prof. Spencer of Melbourne. 



