128 PROCEEDINGS OF THE ACADEMY OF [1899. 



•a compact mass divided into several loljes, of which a long, nar- 

 row ventral one, from the middle of which the efferent duct arises, 

 and a short, broad, dorsal one are the principal. The part of the 

 •organ just described is postseptal. Only the small funnel and its 

 stalk project through the septum into the somite next anterior. 



The testes (fig. 3, t.), are attached to the body floor close to 

 the root of the septum X-XI, and rather near to the middle 

 line. Their products are shed while in early developmental stages 

 into the cavity of somite XI, from which some find their way into 

 X, but most pass into the sperm sacs to complete their develop- 

 ment. The sperm sacs (fig. 3, -ss. and rs^.), are paired, but only 

 the left one has any functional importance. Both arise from the 

 septum XII-XIII, rather high up beside the intestine. Both are 

 simple hollow tubular outgrowths whose walls have the same struc- 

 ture as the septa, being formed of a double layer of the very deli- 

 cate coelomic endothelium, with a very delicate and imperfectly 

 •developed muscular stratum between. That of the right side 

 •{rss.) is almost rudimentary, being narrow and confined to somite 

 XII, in which it ends blindly, or possibly unites with the 

 left after passing around to the ventral side of the intestine. 

 Owing to the delicacy of its walls and the crowding of other 

 organs, this point could not be certainly determined in the three 

 series of sections studied. All appearances are, however, in favor 

 of the interpretation expressed in fig. 3. The left sperm sac is 

 greatly developed. Extending caudad from its origin through 

 somite XII it passes to the ventral side of the intestine, and then 

 occupying more or less approximately the middle line and perfor- 

 ating the successive septa, it continues into somite XX, in the pos- 

 terior part of Avhich it terminates blindly. At each septum it is 

 constricted, but bellies out in the somites, and when filled with 

 developing spermatogonia is the most conspicuous body in a section, 

 not excepting the alimentary canal. Comparing it with the size of 

 the testes it is a matter for wonder how the latter can produce 

 sufficient spermatogonia to keep the former packed as full as they are 

 usually found. The spermatogonia must divide many times. 



The sperm funnels (fig. 3, sj.), have the large size, glandu- 

 lar appearance and narrow lumen so usual in the Enchy- 

 trseidaj, and occupy most of the space by the side of the intestine 

 in somite XI, the posterior septum of which is crowded backward. 



