CAMPOItNIA IM'niUI.TO.'K. 31 



Prti^liilf (fig. <S). Tlicrc is one pair ol' prostates of rather proininciit size ex- 

 tciuliiig i)afallel witii tlie intonsegiiiciital groove reacliing almost across tlie somite. 

 Tlie sliiipc of the prostate resemhU's at the top somewliat a curved fcatlier, the inner 

 apex I)eing helix-like, cnrving backwards. This form appears quite constant and while 

 r fonmi liie length and tlie width of the prostate to vary,! never fonnd one, wliieli did 

 not sliDW the helix-like, convolution. The thickness of the prostate varies considei'- 

 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 prostate was longer, more slender and its longitudinal sides almost parallel, 

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

 tion could bo 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 jtart of the prostate in the muscular layer of the body-wall. The sac con- 

 taining the peinal setiT) is situated immediately anterior to the prostate and somewhat 

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

 with the prostate and spel-mduct. (Figs. 8, 51, 52, 53.) 



X cross section of the glandular part 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 rectangular 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 

 periphery 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 5(!). 

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

 in Deltanin Troyeri (fig. 45). 



This junction of the various male organs is afTeeted 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 muscular part of the prostate they turn and 

 run pai-allel 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 setje (figs. 51, 52, 53). 



Sj)ermafhecn (fig. 13). The spermathecaj consist of very minute botlies, pear- 

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

 the wall in a muscular and glanduLir 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 number and position. 



