CALIFORNIA EUDRILID.i;. _ 31 



PfiAfatc. (fig. S). There is one pair ol' prostates of rather proiiuiieiit size ex- 

 tending parallel with the intersegmental groove i-eaching almost across the somite. 

 The shape of the prostate resembles at the top somewhat a cnrved feather, the inner 

 apex being helix-like, cnrving backwards. This form appears quite constant and while 

 I found the length and the width of the prostate to vary, I never found one, which did 

 not show the helix-like, convolution. The thickness of the prostate varies consider- 

 ably. In some specimens it was almost twice as thick as in others, the increased 

 thickness being caused by a gradual widening toward the inner apex. In some speci- 

 mens the i)rostate was longer, more slender and its longitudinal sides almost parallel, 

 but the convolution was generally always thickened. In most instances the convolu- 

 tion could 1)0 considerably straightened out by a pushing with a needle, but it would 

 when released assume its natural helix-like form. The spermduct connects with the 

 muscular part of the prostate in the muscular layer of the body-wall. The sac con- 

 taining the penial setic is situated immediately anterior to the prostate and somewhat 

 closer to the ventral ganglion in line with the regular setie, but opens in the same pore 

 with the prostate and spermduct. (Figs. 8, 51, 52, 53.) 



A cross section of the glandular ])art of the prostate shows that it is composed 

 of two layers of cells, the outside one containing large cells of flask-like shape, the 

 inner are narrower rectangulai- cells. The contents of both layers resemble each 

 other greatly and are difficult to discern. Both layers of the prostate contain nu- 

 merous blood vessels arranged like radii in a circle, penetrating both of the cellular 

 layers. But the inner layer is seen to also possess a vascular system of its own with 

 many smaller vessels similarly arranged. These vessels are generally wider at the 

 peri])hery of the prostate and narrow toward the center, many if not all collecting in a 

 network of capillaries spreading on the inner surface of the prostate (figs. 55 and 56). 

 Otherwise these vessels do not anastomose. All these vessels are fed by a branch from 

 the ventral vessel of the body, which divides on the prostate into two or three large 

 branches wiiieh again fork toward the apex of the prostate in many smaller ones, as 

 in Deltanin Trntjeri (fig. 45). 



This junction of the various male organs is aflfected in this manner. The two 

 spermducts run jointly on the top of the inner longitudinal muscular layer of the 

 body-wall. When reaching the lower or mnscular part of the prostate they tui-n and 

 run parallel to it. Immediately before reaching the place where the prostate enters 

 the wall, the two spermducts fuse into one duct, the lumen of which then is wider 

 than the adjoining part of the prostate. This duct joins the prostate in the longitudi- 

 nal muscular layer of the body-wall. After reaching the transverse muscular layer 

 this duct joins the pore of the penial seta; (figs. 51, 52, 53). 



Sjicrmntlieca (fig. 13). The sperraathecfe consist of very minute bodies, pear- 

 shaped in outline, and of extremely delicate structure, without any differentiation of 

 the wall in a mnscular and glandular layer. In size, the spermatheca is not much, 

 if any, larger than one-half the width of the somite, when contracted in alcohol. But 

 the most peculiar feature of this organ is that it is variable in miniber and [losition. 



