138 OLIGOCHAETA 



unable to find these, and their presence, with the function attached to them by 

 FRAISSE, seems to me to be unlikely. It is possible that the tubes in question are 

 the nephridial ducts, which we know, from HUBRECHT'S researches (see above), often 

 open on to the exterior at some distance from that point where they first perforate 

 the body- wall. A main objection to the formation of the spermatophores by the 

 tubercula pubertatis is, according to VEJDOVSKY, their frequent occurrence at points 

 somewhat remote from these tubercula. He (VEJDOVSKY) regards the spermathecae 

 as the site of their formation. It is not, however, necessary to go into this 

 suggestion at length, since spermatophores exist in Oriodrilus, where there are 

 neither spermathecae nor tubercula pubertatis. 



ROSA (4) has, therefore, suggested that the glandular protuberance on to which 

 the sperm-ducts open in so many Lumbricidae is responsible for the secretion of the 

 case of the spermatophore. This suggestion is decidedly in accord with the facts. 

 It explains, for example, the large size of the spermatophores in Criodrilus, where 

 the glands in question are largely developed, as well as the fact that they have 

 not been discovered, in spite of diligent search, in Allolobophora complanata, where 

 the swelling at the termination of the sperm-duct is wanting. The suggestion also, 

 according to ROSA, explains the position of the spermatophores ; for they are found 

 'always on the segments which during copulation are placed in front of the male- 

 pores.' In Allolobophora samarigera the spermatophores are, most exceptionally, 

 found dorsally on the fifteenth or sixteenth segments. The pear-shaped spermatophore 

 thins out on all sides into a thin and leaf-like lamella, reminding one in fact of 

 a pine seed. 



Among exotic earthworms spermatophores have only been discovered (by myself 

 39) in the Eudrilidae, and within that family only in the genus Polytoreutus. 

 They have been found in more than one species of the genus, and are in all probability 

 characteristic of it. The spermatophores of Polytoreutus are not at all like those 

 of the Lumbricidae or of Criodrilus, and in fact are peculiar to the genus which 

 they characterize, though somewhat like the immature spermatophores of Tubifex. 

 They are very long, and commonly thicker at one end. They consist of a tolerably 

 thick, transparent axis, to which the spermatozoa are attached, and within which 

 they are but slightly imbedded. 



Finally, the spermatophores of Eclipidrilus may be briefly described. These are 

 stated by EISEX (3) to be glassy transparent bodies ; they are sculptured externally 

 with, a raised spiral line ; the upper extremity of the spermatophore is dilated and 

 spherical. 



