1885.] NEW-ZEALAND EARTHWORMS. 827 



are equivalent to the "soies de remplacemeut " of the locoinotor setae; 

 these, however, are contained within the body-cavity and do not 

 protrude on to the exterior. It is important to notice that the 

 genital setfe, although different in appearance from the ordinary 

 Jocomotor setse, do ncjt diffei' in their disposition ; and, moreover, the 

 aperture of the conjoined vas deferens and prostate duct has a relation 

 to the setfe precisely similar to that which has already been referred 

 to in the case of the nepbridial aperture and the locomotor setEe 

 (see p. 822). The a[)eitures of the vasa deferentia, like those of the 

 nephridia, correspond in position to the outermost setae of the pair. 



§ Female Generative Organs. 



In Acanthod ril us novee selanrlicE and A. dissimilis the ovaries are 

 to be found in the 13th segment, i. e. next to that which contains the 

 posterior pair of testes ; they are attached to the anterior mesentery 

 of this segment close to the middle line. The ovaries are of a very 

 peculiar form ; instead of being round, or, rather, pear-shaped as in 

 Lumbricns, they present the appearance of a flattened circular disk, 

 much folded and plicated ; their resemblance indeed to a vas- 

 deferens funnel is so striking, that T mistook them at first for such 

 a structure, until a microscopical examination revealed their true 

 nature. I find a figure by M. Perrier of the ovary of Perichceta 

 houlleti^, which shows a great resemblance to the ovaries of this 

 Acanthodrihis. It is interesting to note the different positions 

 which the ovaries may occupy in Earthworms : in Lumbricus ihey 

 are situated on the anterior wall of the segment in which they are 

 found, and, as in Acanthodrilus, this is tbe 13th segment of the 

 body ; in PerichcEfa and Microchceta the ovaries are found in the 

 same segment of the body, but upon the posterior mesentery ; in 

 Acnnthodrilus mvltiiwrvs I have to record the position of the ovaries 

 in the same segment, but attached to the anterior margin of the 

 oviduct-funnel and apparently to the ventral body-wall, between the 

 two mesenteries wliich enclose the segment. 



In Acanthodrilus dissimilis, also in A. novce zelandia, the oviducts 

 open separately in front of the ventral pair of setse of each side ; a 

 series of transverse sections through this region show that the 

 apertures bear a particular relation to the outermost of these two 

 setse. There is nothing remarkable in the structure of the oviducts. 

 The oviducts of A. multiporus open by the innermost of the two 

 ventral setae, so that the position is sliglitly different. In all 

 three species there are a series of peculiar glands, two pairs situated 

 in the 11th and 12th segments. The position of these structures 

 in A. dissimilis and A. r.ovce zelandice is shown in the drawing (wood- 

 cut, fig. 3) which illustrates the generative region of A. dissimilis. 

 The general appearance of these glands is not unlike that of the 

 ovaries ; they arc somewhat rosette-shaped, being formed of a much 

 plicated disk, attached by a narrow pedicle to the anterior mesentery, 

 and depending freely into the interior of the segment ; ihe general 



' Nouv. Arch. &o. loc. cif. pi. iii. fig. GO. 



