STUDIES ON EARTHWORMS. 101 



fast arrangement previously adopted, e. g. species of Acan- 

 thodrilus have been described by Beddard (' Proc. Zool. Soc./ 

 1885, p. 814), and by Horst ('Notes of Leyden Museum,' vi), 

 in which the male pores are not posterior to the clitellum, as 

 in the three species described by Perrier, but are within the 

 area of the clitellum. Again, Beddard has described a species 

 of Megascolex (Pleurochseta, 'Trans. Roy. Soc. Edin./ 

 XXX, 1883), in which the genital pore has also this position, 

 instead of the usual post-clitellian position of the remaining 

 species of Megascolex and Perichaeta. 



It seems better, therefore, to use in the future Vejdovsky's 

 plan, and form the following families for the Terricolous 

 Oligochseta : 



1. Pontodrilidse. 



2. Criodrilidae. 



3. Lumbricidse (= Preclitelliani). 



4. Eudrilidse (= Intraclitelliani). 



5. Acanthodrilidse. 



6. Perichsetidse ( + Pleurochsetidse of Vejdovsky). 



7. Plutellidge. 



8. Moniligasteridse. 



In February of this year Mr. F. E. Beddard published 

 ('Ann. Mag. Nat. Hist.,' p. 89) a description of a new 

 species of Perichseta, and of Moniligaster, together 

 with some notes on Perichseta Houileti, E. P., and P. 

 posthuma, Vaillant. P. Ceylonica, Beddard, differs from 

 all other species of this genus with the exception of P. 

 armata, Beddard,^ in possessing a sac, containing one or 

 more penial setae, on each side of somite xviii, in which lie 

 the male pores — an arrangement found, too, in Acantho- 

 drilus. 



Moniligaster Barwelli, Beddard, agrees with Perrier^s 

 M. Deshayesii in having no clitellum, although the genital 

 organs are mature in both species. 



In the new species only the posterior pair of "testes" in 

 somite ix are present. The sperm duct, which appears to have 



1 ' Ann. Mag. Nat. Hist.,' xii, 1883. 



