I9I7-] J. Stephenson : Indimi Oligochaeta. 35;^ 



dia elsewhere) ; '' I am at present unable to say anything about the 

 nephndia" (P. burliarensis); ''no nephridia were observed" (P. 

 hidikalensis) ; " nephridia seem to be present in certain anterior seg- 

 ments only" (P. mirabilis); " the nephridia occur in, at any rate 

 most of the somites ; they are very large and present rosettes of 

 tubules in certain anterior somites" (P. saleitensis). We can only 

 conclude that Bourne's observations on the nephridia of his various 

 species are inadequate in respect of present-day requirements, and 

 are not of much help in identifying his forms ; one can hardly ac- 

 cept his statements, for example, with regard to the nephridial dis- 

 tribution in P. gracilis and P. mirahilis. (3) The ease or difficulty 

 of determining the nephridial condition depends largely on the 

 condition of the specimen ; it is easiest in a well-preserved spirit 

 specimen, as the nephridia are then opaque, but in badly preserved 

 material it may be impossible. Even much later than Bourne's 

 day the most experienced investigators have at times been under 

 the necessity of levising their accounts of the nephridial conditions, 

 so Benham (4, 6 ,-~Plagiochaeta ricardi and montana at first sup' 

 posed micronephridial, later recognized as meganephric) ; Michael- 

 sen (ir, 14,— Eudichogasler ashworthi at first supposed' microne- 

 phridial, later recognized as having both mega- and micronephridia). 

 Thus I do not think it is unfair to leave aside the nephridia of 

 Perichaeta stuarti altogether. When Bourne says "I have not 

 observed any nephridia," it may simply have been for want of 

 sufficiently close observation, or the specimen may have been badly 

 preserved ; in any case we are dealing with the early days of Oligo- 

 chaete research, with a preliminary communication which was 

 only meant to be a first survey of the field, and written at a time 

 it was not known even what characters were of generic value. We 

 must admit that we know nothing about the nephridia, even by 

 inference. 



I have, 1 think, shown that there is pretty certainly a mistake 

 in Bourne's statement concerning the position of the gizzard; that 

 there is no ground at all for supposing a separate male pore in seg- 

 ment xviii, or that the spermathecal apertures are necessarily in 

 furrows 7/8 and 8/9 (though this last point is relatively unimpor- 

 tant) ; the intestinal caeca, whether they were accidental inflations 

 of the gut-wall or not, would not be of generic importance; and, 

 finally, we are in the dark as regards the nephridia. In all other res- 

 pects the worms in the present collection resemble Perichaeta 

 stuarti; and I have therefore, after much hesitation, decided to 

 unite them in the same genus, the diagnosis of which now runs as 

 follows : — 



Genus Hoplochaetella, Mchlsn. emend. Stephenson. 

 Setae in rings. Calcareous glands four pairs, in x-xiii. Micro 

 nephridia throughout the body ; meganephridia in addition from xx 

 onwards, one pair per segment. Two pairs testes, free in x and xi. 

 Two pairs long coiled prostates, opening on the posterior part of xvii 

 and the anterior part of xviii, or in grooves 17/18 and 18/19. Vasa 



