ZooL.— Vol. II.] RISEN— OLIGOCHMTA. l6l 



The most anterior nephridia are probably in II, beyond 

 doubt in III. The intestine which iwS unusually narrow, is 

 nipped by the septa, and the gizzard \^ very rudimentary; 

 its muscular layer is of about the same thickness as the 

 muscular layer of the body-wall — not thick enough to cause 

 the intestine to bulge out. The sacculated intestine com- 

 mences in somite XVI. The -pharynx also is developed 

 ventrally and furnished with subpharyngeal glands. Strong 

 se-ptal glands extend back to somite VIII, there being none 

 in somite IX. The sferniatheccB are strong, each with a 

 single, rather large diverticle pointed backwards. The 

 diverticle joins the muscular part of the spermatheca close 

 to the body-wall. The sperm-ducts join the muscular part 

 of the prostate in the body-wall. Septa VIII to XIV are 

 somewhat thickened. The septa on all the anterior somites 

 are attached to the body-wall half way between the inter- 

 segmental grooves, in line with the setae. The interval 

 between setge a and b is slightly less than that between c 

 and d. In a general way the arrangement of the setae 

 resembles that of AT. Troyeri. 



PLUTELLIN^. 



Nomenclature. 



In his Monograph on Oligochseta Beddard refers all the 

 species of Plutellus and Argilophilus to the genus Mega- 

 scolides. The genus Plutellus was created for a worm with 

 alternating nephropores, meganephridia, five pairs of sperm- 

 athecse and with calciferous diverticles in X, XI, XII. The 

 genus Megascolides was established by McCoy for a worm 

 with plectonephridia, two pairs of spermathecse, one diver- 

 ticle of the intestine, etc. My genus Argilophilus was 

 made for species with meganephridia, two pairs of sperm- 

 athecae, no calciferous diverticles, alternating nephropores. 

 If the various species are to be bunched under one genus, 

 then there can be no doubt but that the genus Plutellus 

 must be retained. But I think that we are not yet ready to join 

 plectonephric species with meganephric ones in one genus. 



