1892.] SPECIES OF EARTHWORMS. 685 



uniting, as Peiiier thouglit might be eventually necessary, the two 

 genera Perionyx and PeriehcBta. Vaillant in thus uniting these 

 genera errs, in my opinion, as much on the one side as does 

 Benham ^ on the other, when he relegates the two to different 

 families. 



I have recently studied four species of Perionyx — one of which I 

 referred to some years since in connexion with the remarkable 

 variations in structure exhibited by individuals ; the second species, of 

 which I owe examples to the kindness of Dr. Michaelsen, has been 

 lately described by that naturalist " as Perionyx gruenewaldi. The 

 specimens of the two remaining species were sent to me some time 

 since by the kindness of Dr. King ; they are from Seebpore. Putting 

 together what we know from Perrier's investigations, from my own ^ *, 

 from those of Michaelsen ', Rosa ", and Bourne \ and what I have to 

 say here with regard to this genus, we may thus define it : — 



Genus Perionyx, Perrier. 



Perionyx, E. Perrier, Nouv. Arch. Mus. t. viii. p. 126. 



Setce forming complete circles, present as such upon all the 

 seyments of the clitellum; male pores close together upon a depressed 

 area on segment xviii., with a group of rivodijied setce in some species 

 near to each orifice; atria lobate ; spermatothecce two {or three) 

 pairs in {yii.) viii., ix., with or without diverticula; nephridia 

 paired; no specially thickened septa ; no cceca. 



The above definition of the genus may now be supplemented by a 

 few remarks. These remarks will chiefly concern the species of the 

 genus ; the type species, P. excavatus, has been described by Rosa 

 as well as by Perrier, and to a more limited extent by myself. But 

 I am not quite certain, after comparing two out of the three species 

 described here in addition to Michaelsen's P. gruenewaldi, as to 

 which of them is really Perrier's P. excavatus. 



The worms from Manila agree very closely with Michaelsen's 

 P. gruenewaldi. Michaelsen distinguishes his species from that of 

 Perrier on the following grounds : — The pigmentation is so marked 

 that, if P. excavatus were of the same dark violet colour above, 

 Perrier would hardly have omitted to notice the fact : secondly, the 

 penial setae of P. gruenewaldi appear to distinguish it from P. 

 excavatus: thirdly, the position of the gizzard; this organ is fixed 

 by Perrier in the twelfth segment ; Michaelsen, on the other hand, 



1 " An Attempt to Classify Earthworms," Q. J. M. S. vol. xxxi. p. 247. 



2 " Oligocbiaeton des Hamburger naturhist. Mus. iv.," JB. Hamb. wiss. Anst. 

 viii. p. 33. 



^ " Descriptions of some new or little-known Earthworms, &c.," P. Z. S. 

 1880, p. 308. 



^ " Note on some Earthworms from India," Ann. & Mag. Nat. Hist. ser. 5, 

 xii. p. 217 (1883). 



" " Beschreibung der Ton Herrn Dr. Fr. Stuhlmann auf Sansibar, &c.," JB. 

 Hamb. wiss. Anst. is. 



'^ " Perichetidi di Birmania," Ann. Mus. Civ. Geneva, ser. 2 a, vol. vi. p. 157. 



"> " On Indian Earthworms," P. Z. S. 1886, p. 662. 

 Proc. Zool. Soc— 1892, No. XL VI. 46 



