534 Illinois State Laboratory of Natural History. 



(posterior part of XYIII to the anterior part of XXIV). In 

 one specimen in which they were counted the number varied 

 from fifty to sixty on each side of each somite. They are 

 small pyriform or globoid bodies grouped about the vas 

 deferens, into which they empty, in most cases by separate 

 ducts. The vas deferens (PL XLVIL, Fig. 35, rd) is an 

 extremely line, straight tube reaching to ganglion XYIII. 

 At this point the duct suddenly enlarges into a very conspic- 

 uous epididymis or sperm-sac (ss). This much convoluted 

 tube continues through several somites but gradually dimin- 

 ishes in diameter. By somite XV it has become only one 

 half or one third of its greatest size, and in XIY the convo- 

 lutions become more open and soon the duct is merely wavy. 

 This region is the ductus ejaculatorius (de), which passes 

 forward in a long loop to ganglion XI, at which point it 

 turns sharply mesiad and caudad and returns to the terminal 

 organ. Eegarding all of the latter as the atrium, it consists 

 of two more or less elongated curved conical horns (j>) 

 directed longitudinally. At their bases they rest on a pair of 

 swollen pedestals covered with a layer of prostate glands, 

 which also extend somewhat on to the bases of the cornua 

 themselves. This basal region, the two halves of which 

 embrace the nerve cord between them, may be separated 

 quite to the basal integuments, where each half communicates 

 by a separate orilice with a small bursa. The median part 

 of the atrium appears to be represented by these two basal 

 halves of the cornua. 



The ovaries (PI. XLVIL, Fig. 35, or) are a pair of long 

 slender sacs, each doubled on itself, with both ends in somite 

 XII, and the loop reaching far back along the median line, 

 ventral to the alimentary canal, to the neighborhood of 

 ganglion XVII. From somite XIY to somite XYII the two 

 ovarian sacs lie side by side; just anterior to ganglion XIY 

 they diverge, the closed end of each arching upwards around 

 the pharynx ; and they end close together, near the median 

 line. The external ends of each, on the other hand, retain 

 their ventral position and join beneath the nerve cord at the 

 common external opening (• 9 ). 



