280 CAT.IFORNIA ACADEMY OF SCIENCES. 



in xviii. Ovaries in xiii. Oviducal pore in xiv. Spernni- 

 thecas, one pair or none in viii or ix, with no or rudiment- 

 ary diverticula. No penial seta; and no subnervian 

 vessel. No blood vessels on the nephridia. 



Among other genera which Ocnerodrilus resembles, 

 Pygmasodrilus appears rather prominently. I will here 

 only call the attention to the long prostates which are 

 differentiated into a muscular and a glandular part, and 

 which extend through many somites, just as in Ocnero- 

 drilus and Gordiodrilus. The swelling or muscular en- 

 largement possessed by some species of Ocnerodrilus 

 resembles greatly that of Pygmasodrilus. The greatest 

 difference between that and our genus is the arrangement 

 of the ciHated rosettes which in Pygm;:Kodrilus are in- 

 vested by the sperm-sacs, while in both Ocnerodrilus and 

 Gordiodrilus they open independently. The paired di- 

 verticulum of the tEsophagus is also found in Pygniieo- 

 drilus. 



Of all the various characters in which Ocnerodrilus 

 and Gordiodrilus resemble each other and in which they 

 also differ from the genera of Beddard's Cryptodrilidie, 

 the absence of bloodvessels on the nephridia and the 

 single cell structure of the glandular part of the atrium 

 are the two most important ones. The character derived 

 from the presence or absence of diverticula on the 

 spermatheca is weaked by the fact that the diverticula of 

 this organ vary greatly in size, or are entirely absent in 

 some species of the same genus. The absence of a gizzard 

 is of late consigned to a mere species character (by 

 Beddard), and the form and arrangement of the seta; 

 can in no way be considered of equal value to the ar- 

 rangement of the inner organs. The presence of septal 

 glands in our two genera is also of great importance, as 

 connecting them with lower forms. The safest we can 



