22<i OLIGOCHAETA 



The genus Eclipidrilus does, it is true, agree with the Lumbriculiclae in the 

 characters mentioned by VEJDOVSKV. The setae are most unquestionably identical in 

 their character with those of the Lumbriculids. When, however, we turn to the other 

 organs of the body, we find divergences from the Lumbriculid type of structure. 

 This is especially the case with the male efferent apparatus, which, however, 

 evidently requires re-examination. The long spermiducal glands communicate with 

 a retractile penis, apparently very similar to that of the Tubificidae ; the Lumbriculidae 

 have no penis, with the exception of Stylodrilus and Alluroidea, in which genera 

 there are a pair of non-retractile penes, recalling those of certain Eudrilids. The 

 spermiducal gland, too, is covered for part of its course with spirally-arranged 

 muscular fibres, similar, as EISEN has remarked, to those of Camptodrilus. 



It is in the middle that the gland is invested with these spiral muscles. And 

 here its diameter is much narrower than elsewhere, dividing the entire tube into 

 two divisions ; in the lower part of the tube there are three apertures, placed one 

 behind the other, by which its cavity communicates with the body-cavity; the walls 

 of this tube are muscular, but the lining is, of course, epithelial. Freely suspended 

 within this tube is another tube, which does not reach down so far as the first ; 

 at the point where it ends, a little way in front of the commencement of the penis, 

 it has a circular orifice. The long sperm-sacs occupy about the same segments as 

 the remarkable efferent ducts, i.e. x-xv. There appear to be three pairs of gonads, 

 which EISEN calls ' ovaries,' in segments ix, x, xi. The nephridia have a swollen 

 glandular part immediately after the funnel, as in other Lumbriculidae, Naidoniorpha, 

 and Tubificidae. There seem to be no specially enlarged hearts ; those of segment x 

 are extended backwards, no doubt in relation to the development of the sperm-sacs. 

 There is but one species, viz. Eclipidrilus frigidus, from a spring in the Sierra Nevada 

 of California, at an altitude of 10,000 feet. I attempt no definition of either species 

 or genus. 



FAMILY TUBIFICIDAE. 



DEFINITION. Aquatic Oligochaeta of small size and slender build, fresh-water or 

 marine. Setae of three kinds, capilliform, pectinate, and uncinate, the former 

 two kinds, when present, found only in the dorsal bundles. Dorsal and ventral 

 blood-vessels, connected by perivisceral trunks, in every segment of the body. 

 Testes in X, ovaries in XI, sperm-ducts always terminating in spermiducal gland, 



