RKPOK'l' OX TlIK OLICOCIU.TA liKNHAM. 26."i 



wliicli of course tliey must pass on the way to the exterior. But 

 in most of these cases tliei-e is no doubt as to the nature of the 

 chamber ; it is provided witli a glandular linini;-, oi- receives the 

 necks of the gland cells of the prostate, and thougii we are in 

 ignorance as to the exact function of this secretion, yet it appears 

 probable that it takes some share in the process of copulation. 

 In the present worm, however, the sac which contains the sperm- 

 atozoa is absolutely non-glandular — there is neither prostate, nor 

 prostate cells outside it, nor glandular cells lining it. The wall 

 is strongly muscular, far more muscular than is the atiium in 

 other aquatic Oligocluetes, and in this respect resembles the 

 muscularity of the spermatheca in many Tubificids. At any rate, 

 we have to note the entire absence of a spermatheca corresponding 

 to that of PhrPodriJus. 



In all the species of this genus the spermatheca is a long sac 

 extending through two or more segments and opening near the 

 anterior margin of segment xiii. This is quite an exceptional 

 position for this organ, in the class, for it is almost universally in 

 front of the male pore, though in certain of the Lumljriculidie it 

 is behind the pore. 



The idea occurs to one that in PhreodrUoides tiie pore of the 

 spermatheca has passed forwards into segment xii., and has 

 become coincident with the male pore. But there is nothing 

 analogous to such a fusion throughout the Oligochfeta, and a more 

 reasonable explanation is that the atrium has become a reservoir 

 for the spermatozoa, and that copulation does not occur, that the 

 muscular sac (or " autospermatheca ") discharges its own speiin- 

 atozoa on its own ova, during the formation of the cocoon. 



But there is another feature in which this new genus ditters 

 from Phrrodi-iliis — in tliat genus the sperm duct opens into a 

 more or less tubular organ lined with glandular cells and termed 

 the " atrium," which in tui-n opens through a " penial sac " lined 

 by flatter cells, and surrounded by muscles This .sac is quite 

 small or evanescent in P. kfiniiipleupusis (10), but is of considerable- 

 size in P. Incuxfrls and othei'S (see Benham, 4), and further, in 

 most .species the jujre is at the end of a conical pi-otrusible organ 

 lying in this sac. 



From a mert^ inspection of a figure, the male apjjaratus of 

 P]iri'()d}-il()idpx appears to be readily comparable with that of 

 P. krr<iiit'lptixlx, Michaelsen, and P. /acusfris, Benham, were it not 

 that what is a highly glandular sac (atrium) in these two .species, 

 is a non-glandular, highly muscular sac in PhreodriJoides ; and it 

 appears that the "penial chamber" of the latter — partly 

 glandular as it is — niay represent both tlie atrium and the penial 

 sheath of such a foi'in as P. Jaciixfrix. On the other hand, there 



