1899.] NATURAL SCIENCES OF PHILADELPHIA. 129 



Of a somewhat truucate pyriform shape, they are bent on them- 

 selves in such a manner that their mouths ai'e directed toward the 

 openings of the sperm sacs, Avhile their stalks perforate the septum 

 ventrad to the latter and pass into the sperm ducts. The sperm 

 ducts (fig. 3, sd. ) are remarkably long — about fifteen times as long 

 as the sperm funnels — and form a pair of much coiled and twisted 

 loops reaching in a typical example into somite XVIII. That of 

 the right side enters the ovisac by its mouth and remains coiled 

 within it by the side of the aggregated ova for the remainder of its 

 course. In fig. 3 it is represented, for the sake of simplicity, as a 

 straight loop. The left sperm duct lies free in the body cavity^ 

 passing through the septa by the side of the left sperm sac, ventrad 

 to which most of its coils lie. The sperm ducts are composed of a 

 cubical epithelium and are ciliated throughout. Before entering 

 the atrium in somite XII the recurrent limbs of the spei-m ducts 

 expand into narrow fusiform sacs (fig. 3, ss.), having glandular, 

 epithelial and muscular walls, which receive the ductules of a group 

 of unicellular spermiducal glands. This structure probably serves 

 to form and eject the spermatophores. A narrow curved duct, 

 which is also provided with some unicellular glands, perforates the 

 mesial wall of the atrium and opens into its lumen. 



Unlike the remainder of the male efferent apparatus, the 

 atrium (fig. 3, a), is, in part, of ectodermal origin, as is indi- 

 cated by the pigmented lining epithelium. It is a spheroidal thick- 

 walled partly eversible sac, with an internal cavity having a raush- 

 roomlike shape in the retracted organ. Its walls are composed of 

 a cuticle-covered, rather deep, pigmented and perhaps glandular 

 epithelium, surrounded by a thick muscular layer in which the 

 fibres are partly longitudinal, but largely radial, especially about 

 the place of entrance of the sperm duct. A number of grouj^s of 

 unicellular glands are attached to the organ, and probably emptji'- 

 into its lumen. The external opening is described above. 



The ovaries (fig. 3, ov.), arise from the floor of the body- 

 cavity at the foot of the septum XI-XII. The ovipores have the 

 usual Enchytr?eid form and relation. Their position is noted 

 above. A single ovisac (fig. 3, ovs.), is present. This is pushed 

 back from the septum XII-XIII, just dorsad to the sperm sac, 

 which behind this point displaces it to the right for the greater 

 part of its length. The sac is long and cylindrical, much con- 



