50 CALIFORNIA ACADEMY OF SCIENCES. 
typhlosolar vessel, which is entirely dorsal, is many times smaller than the longitudi- 
nal dorsal vessel, but posterior to that somite the typhlosolar vessel assumes a larger 
size, almost equalling the main dorsal vessel. In the anterior somites the typhlosolar 
region does not project down in the intestine, but is only somewhat wider than the 
balance of the intestinal wall. The typhlosole in this part appears to be filled with a 
fibrous and spongy mass, in which, however, I have seen no distinct nuclei (fig. 134, 
c. ».). These cavities are more oblong at the walls, more round or angular at the 
center, where several larger cavities are seen. At the upper margin of the typhlo- 
sole this fibrous body gives room to two large and several smaller longitudinal canals, 
one at each extremity of the typhlosole, all separated by muscular fibers or cell-like 
chambers. In fig. 136 the fibrous nature of the interior of the typhlosole is somewhat 
more pronounced than it should be, the fibers appearing rather more regular than in 
reality, though the appearance is always as if the majority of the fibers radiated in a 
fan-like way from the central spongy mass. This part of the posterior typhlosole is 
in cross-section deltoid, with the point projecting into the cavity of the intestine 
(136, ty). The size of the typhlosole varies with the individual specimen. 
Spermatheca (figs. 81 to 86). There are two pair of spermathecze in viii and 
ix opening in the intersegmental grooves between vii and viii and yili and ix. The 
spermthecal pores are found in front of and slightly outside of the second sete. As 
regards the size the spermathecze may be said to be very large, but unequal, as we 
seldom find two of the same size. One or two are generally developed at the 
expense of the others and fill all the available space in the somites, frequently pushing 
the septa into the nearest somites. Seen in a transverse section of a segment the 
larger spermatheca may be occupying as much as three-fourths of the cavity (fig. 86). 
The spermatheca consists of two distinet parts, of which the upper is by far the largest, 
rounded in outline or potato-like with comparatively thin walls (fig. 82a). This part, 
though somewhat warty, carries no diverticula and there are no smaller cavities for 
the storing of the spermatozoa. The lower muscular part is twisted, and set obliquely 
to the former, but can in no way be said to form any kind of a diverticulum (figs. 81 
and 82). The muscular layer, which is a direct continuation of the longitudinal layer 
of the body-wall, is only arranged in one way forming a circular muscular stratum of 
the spermatheca much thicker at the base than at the top (fig. 82 /.m). This muscular 
layer extends to the upper part of the spermatheca (82 a), but is here quite narrow. 
The inner glandular layer is singularly well developed (figs. 82, g/. ¢.; 84 g/l. ep. and 
83), projecting inwards in large folds like the epithelial folicles of the intestine. 
Secretions accumulate as a large whitish mass in the upper part of the sperm- 
atheca, and are seen to be sparingly mixed or streaked with spermatozoa. But 
the most characteristic part of the spermatheca is the interlacunary system for the 
storage of the spermatozoa in the lower or muscular part. A section of this part shows 
(figs. 82, 83 and 84, /. s.) a row of chambers imbedded between the epithelial cells, 
or between them and the muscular layer, and which connect more or less directly 
with the cayity of the spermatheeca by means of narrow passages (fig. 83 p.) Some 
