1893.] DISTRIBTTTION OF EABTHWOEMS. 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 

 Lumbncus and Allolobopliora, and also, though to a less extent, 

 Allurus, are nearly world-wide in range. I beUeve that this ex- 

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

 This opinion is based upon the follo\ving facts. In such countries 

 as Australia the presumably indigenous fauna (Cryptodrilus, Mega- 

 scolides &c.) is met with 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 Palaearctic and Nearctic regions specifically different 

 from forms living wii;hin those two regions. If the exotic Luynbri- 

 cidce were indigenous to such countries as Xew Zealand and South 

 America, it might be fairly expected that they would show at the 

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

 few Perichcetidce 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- 

 Ameiican 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 Pontoscolex. The latter genus has three 

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

 Pontoscolex corethruiiis, 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 Eud,rilus 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 relief the 

 characteristic features of the several regions; for instance, PericJicefa 

 and Merjascolex and also Perionyx are rare in tropical Africa. 

 Cryptodrilus is only known from the Neotropical region by one 

 species doubtfully referable 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 

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

 may be drawn up : — 



pAL-ffiAECTic EEGION. — Lumhricus, Allohboiihora, Allurus, Grio- 

 drilus. 



Neaectic eegion. — Lumhricus, Alloldbophora . 



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



