50 CALIFORNIA ACADEMY OF SCIENCES. 



typlilosolar vessel, which is entirely dorsal, is many times smaller than the longitudi- 

 nal dorsal vessel, but posterior to that somite the typlilosolar vessel assumes a larger 

 size, almost equalling the main dorsal vessel. In the anterior somites the typlilosolar 

 region does not project down in the intestine, but is only somewhat wider than tlie 

 balance of the intestinal wall. The typhlosole in this part aj^pears to be filled with a 

 fibrous and spongy mass, in which, however, I have seen no distinct nuclei (fig. 134, 

 c. r.). 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. 13G the fibrous nature of the interior of the typhlosole is somewhat 

 more pronounced than it should be, the fibers ai^pearing rather more regular tlian 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 

 (18(), Uj). The size of the typhlosole varies with the individual specimen. 



Spcnna/hera (figs. 81 to 86). There are two pair of spermathecre in viii and 

 ix opening in the intersegmental grooves between vii and viii and viii and ix. The 

 spermthecal pores are found in front of and slightly outside of the second seta?. As 

 regards the size the spermathecje 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. 80). 

 The spermatheca consists of two distinct parts, of which the upper is by far the largest, 

 rounded in outline or potato-like with comparatively thin walls (fig. 82 a). 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/. e.; 84 gl. ep. and 

 83), projecting inwards in large folds like the epithelial folicles of the intestine. 



Secretions accumulate as a large whitish mass in the ujiper part of the sj^erm- 

 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, I. 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 cavity of the spermatheca by means of narrow passages (fig. 83 p.) Some 



