3IO CALIFORNIA ACADEMY OF SCIENCES. 



in some specimens the cells commence much more an- 

 teriorly than in others, but the nephridia in the posterior 

 part — the fourth quarter — of the body are always covered 

 with the same quantity of cells and are of the same 

 large size. This is precisel}' the case in Ocnerodrilus, 

 in the various species of which the nephridia are fairly 

 constant in size and form and characteristic of the species. 



Setce (figs. 9 and lo). The setce are all sigmoid and of 

 the regular lumbricid pattern and in couples of two, or 

 8 in each somite. The setee in the three somites of 

 the genital zone are about ^ smaller than those outside 

 of the zone. The free end of the seta is generally 

 sculptured with small pointed cavities, but I also found 

 some set£e in which those cavities could not be defined. 

 In this species all the seta? in the genital zone were pre- 

 sent and I think that this will prove a constant character- 

 istic by which this and the following species may be 

 distinguished. The common setse in this species are a 

 trifle wider, but not quite as long as in the following 

 species. 



The cephalic ganglion (fig. 22), is narrower than in 

 Ocnerodrilus and the lobes less prominent. The ventral 

 ganghon is much nipped by the septa and is raised up 

 above the intersegmental furrow in a way which I have 

 not observed in Ocnerodrilus. The ventral ganglion 

 sends out two pair of large nerve ganglia toward either 

 side. The anterior one of these is situated in the ante- 

 rior quarter of the ganglion and is by far the smallest, 

 only half as wide as the posterior ganglionic branch, 

 which is broad, paired and situated quite close to the 

 posterior septum, about midway between it and the seta^. 



The vascular system (fig. i) is closely allied to that of 

 Ocnerodrilus. The ventral vessel is connected with the 

 dorsal vessel by two pair of large hearts in x and xi. The 



