1895.] MB. F. E. BEDDARD ON NEW EABTHWOKMS. 227 



regions of South America. Michaelsea does not pretend to 

 definitely assign this species to the genus Oryptodrilus ; he only 

 placed it there (with a query) pending the revision of the Crypto- 

 drilidae. The classification of that family is one of the most 

 difficult tasks for the systematist ; the differences are so slight 

 between species and species that the boundaries of genera are 

 extremely hard to draw. I believe, however, that it is possible to 

 define the genus Microscolex by the following characters : — 



(1) Nephridia paired, beginning in the second to foui'th 



segment. 



(2) Male pores upon segment xvii. 



(3) Sphermiducal glands tubular, provided generally with 



penial setse. 



This definition is naturally somewhat wider than that adopted 

 by Eosa, the founder ol' the genus. But a number of new forms 

 which I shall describe immediately necessitate an expansion of the 

 genus. They do not present a sufficient number of salient differ- 

 ences to warrant the formation of a new genus. I have already 

 proposed to include my genus Rhododrilus in Microscolex, and I 

 do not see sufficient reasons for retaining the genus Deltania of 

 Eisen. Gryptodrilus spatulifer of Michaelsen must, I think, espe- 

 cially in view of the new species to be described here, be relegated 

 to Microscolex. The size is really the only bar to its inclusion. I 

 find a good many individuals of Microscolex duhius which are really 

 quite as large as many individuals of Microscolex spatulifer. The 

 distribution of this genus is interesting. It is the commonest 

 earthworm in point of number, and nearly so in point of species, 

 in the temperate parts of South America. I quite agree with 

 Rosa that it has probably been introduced into Italy and possibly 

 also into Australia ; I described a species from Teneriffe and one 

 from Algeria which are very 1 lively to be regarded, in the same 

 way. 



The remaining species occur in New Zealand {Microscolex miau- 

 tus and M. novce-zealandice) and in California (the genus Deltania 

 of Eisen). 



Dr. Michaelsen's collection contained examples of the following 

 species : — 



1. Microscolex spatulifer (Mich.). 



2. Microscolex ditbius (Fletcher). 



3. Microscolex griseiis, n. sp. 



4. Microscolex michaelseni, n. sp. 



5. Microscolex corralensis, ii. sp. 



6. Microscolex diversicolor, n. sp. 



7. Microscolex longiseta, n. sp. 



8. Microscolex robustus, n. sp. 



9. Microscolex modestus, Eosa. 



10. Microscolex gracilis, n. sp. 



11. Microscolex papillosus, n. sp. 



It will be seen, therefore, that this collection contains a large 

 number of new species ; evidently South America is the head- 

 quarters of this genus as it is of Acanthodrilus. 



15* 



