1892.] NEW SPECIES OF EA RTHWORMS. 137 



species as the other two, but I find that it is an Enchytrseid, the 

 anatomy of which, however, I have not yet worked over. 



Of the two other specimens one remains entire, and was returned 

 to the British Museum, the drawing of the external surface (Plate 

 VII. fig. 1) being taken from it; the second was partially cut into 

 sections — after being opened and examined — the anterior twenty 

 somites being cut sagittally, the posterior portion transversely. 



The chief characters of the worm may be summed up as follows : — 



(1) The eight chcetce are isolated, though they are not all 



equidistant. 



(2) The cUtellum is complete, and occupies somites xiii. to xviii. 



(3) The male pores are on somite xviii. 



(4) The nephridiopores alternate in position, one series being in 



line with the chsetse "3," the other with the chsetse "4." 

 There are (5) one pair of testes in somite x. ; (6) one pair of 

 sperm-sacs in somite xi. ; and (7) four pairs of spermathecce, 

 without diverticula, in somites vi., vii., viii., and ix. 



(8) The cylindrical prostate lies in somite xviii. 



(9) The gizzard occupies somite v. ; there are no definite 



oesophageal diverticula. 



The Earthworm which appears to agree most clearly with this 

 diagnosis is Plutellus heteroporus ^ from Pennsylvania; but this worm, 

 according to Perrier's description, presents two very striking anom- 

 alies, which do not occur in the present instance : («) the nephridia 

 are entirely confined to one somite, i. e. the funnel does not perforate 

 the septum ; {b) the " ovary " is placed anteriorly to the testes. 



But these two peculiarities are anomalous, not amongst Earthworms 

 only but amongst all the Oligocliceta ; the post-septal position of the 

 nephridiostome is indeed totally at variance with the arrangement met 

 with throughout the whole group of Chcetopoda ; hence, we must look 

 with very great suspicion on these supposed characters, and indeed 

 Perrier himself, iu writing of the presumed " ovary " in the tenth 

 somite, recognizes its abnormal position and expresses himself, not 

 only with great caution, but also with a good deal of doubt — "Mais 

 nous devous dire qu'a cet egard notre conviction est loin d'etre aussi 

 complete qu'en ce qui concerne les testicules." 



Most zoologists working on this group have thrown doubts on the 

 accuracy of these supposed facts, and this without impugning the 

 carefulness of M. Perrier, for he had two specimens only, and these, 

 having lain in spirit for 50 years and more, were in a very bad 

 condition of preservation ; moreover, his statements were drawn from 

 observations on the dissected specimens, which are not so likely to 

 be correct as tbose obtained from examination of serial sections. 



We must then remove these two characteristics from the diagnosis 

 of the genus Plutellus, and thereby we bring the woim into accord 

 with what has become regarded as the normal condition of things. 



I believe the worm which forms the subject of this communication 



1 Ed. Perrier, Arch, de Zool. Exper. ii. 1873. 



