128 OLIGOCHAETA 



the body ; he suggests that the same may be the case with the Oligochaeta, in 

 many of which the spermatophores seem to be attached to the outside of the body 

 'anywhere.' It is just possible that spermatozoa may be conveyed a short distance 

 by the alimentary tract and then make their way out to fertilize the ova. In 

 connexion with the above suggestion it may be noted that VEJDOVSKY could not 

 find in a single case even one spermatozoon in the albumen of the cocoon. 



The above, however, are rare exceptions to the rule that the spermathecae end 

 blindly in the body-cavity. Among the lower Oligochaeta the organs are generally 

 simple pouches without any diverticula ; this is so with the Naidomorpha, the 

 Tubificidae, the Lumbriculidae (except RhyncJtelmis and Swtroa), the Phreoryctidae. 

 and the Moniligastridae. Of the aquatic families the Enchytraeidae alone are usually 

 provided with one or more diverticula ; the Lumbriculidae are sometimes provided 

 with diverticula at least Sutroa and Rhynckelmis are. The higher Oligochaeta, as 

 a rule, have diverticula ; this is the case with the families Perichaetidae (a few 

 exceptions), the Acanthodrilidae (also a few exceptions), the Cryptodrilidae (like the 

 others with a few exceptions). The members of the two families Lumbricidae and 

 Geoscolicidae never possess diverticula. 



In the family Eudrilidae there are sometimes spermathecae met with ; this 

 statement requires qualification to the extent that spermathecae of the type hitherto 

 considered are sometimes present ; the majority of the members of that family have 

 spermathecae of a totally different morphological nature, which are described further 

 on. In those cases where spermathecae derivable from epidermic invaginations 

 (probably, for that fact has not been actually proved) occur, these organs are 

 invariably placed far back in the body, the most forward position being seen in 

 the genus Heliodrilus, where they are in the tenth segment ; the spermathecae are 

 always unpaired and of course open in the median ventral line. They never possess 

 diverticula, and, indeed, appear to be of limited functional importance, as they have 

 not been observed to contain sperm ; in Heliodrilus, however, the spermatheca is of 

 great length, extending from its external aperture on the tenth segment as far back 

 as the fifteenth. 



When diverticula are present, they are of varying degrees of importance ; they 

 also vary in number ; in the Perichaetidae there is, as a rule, only one diverticulum, 

 which is often of considerable size ; two diverticula are found in various Acantho- 

 drilidae and Cryptodrilidae ; in Octochaetus multiporus there is a circle of small 

 diverticula round the external aperture of the spermatheca. There are two facts of 

 interest to be noted in connexion with the diverticula ; in the first place they are 

 of slightly different structure from the pouch of which they are appendages ; secondly, 



