NEW SPECIES OF OCNERODRILUS. 277 



too early to successfully generalize as regards the rela- 

 tionship of these worms, as it is evident that a whole class 

 of worms must exist which forms connecting Hnks between 

 the land and water Oligochi^tge, and of which class so far 

 only very few genera are known. They have escaped 

 the casual collectors by their minuteness, while the stu- 

 dents of this class of worms have had only little oppor- 

 tunity to collect in tropical countries. When these 

 minute Oligochastaj have become better known we will be 

 able to generalize without running the risk that the next 

 investigator will, with equal propriety, upset all our views. 

 While Gordiodrilus in many respects greatly resembles 

 Ocnerodrilus, it appears to me that it differs too much 

 and in too many important points to be placed in the same 

 family. As Benham remarks, the affinities of both genera 

 are greatest with many genera of the large family of 

 Cryptodrilidai, least of all perhaps with Cryptodrilus. 



From Gordiodrilus our genus differs principally in 

 having salivary pharyngeal glands. Gordiodrilus has 

 none. Also in having a pair of oesophageal pouches, 

 while Gordiodrilus has only one. This latter is very 

 differently constructed from the pouches in Ocnerodrilus. 

 In Gordiodrilus the prostate and the sperm duct open in 

 different pores, similarly as in Acanthodrilida?, while in 

 Ocnerodrilus the prostate and sperm duct open in the 

 same pore. In Ocnerodrilus the male pore is invariably 

 found in somite xvii, while in Gordiodrilus it opens in 

 somite xviii. The prostates in this genus vary consider- 

 ably, in one species opening in somites xvii and xviii {G. 

 rohiisttis), in another in xviii and xix ( (?. elcgans), and 

 in another in xx and xxi {G. tenuis). 



The following comparative table will show the differ- 

 ences and similarities of the two genera: 



