1905.] NATURAL SCIENCES OF PHILADELPHIA. 381 



neck, which penetrates the septum and joins an irregular massive region 

 in which the canal is much folded, with granular coalesced walls and 

 irregular lumen in the anterior part, while in the posterior part the 

 lumen becomes more regular and provided at intervals with ciliated 

 ampullge. From this portion an elongated lobe passes caudally and 

 medially along the ventral blood-vessel. In this lobe are four canals 

 arranged in two loops, the proximal one of which contains ciliated 

 ampullae, while the distal one lacks cilia and, after returning to the 

 massive region, passes into a large thick-walled efferent canal, the 

 lumen of which exhibits a few irregular lateral diverticula, and which 

 finally opens to the exterior by a pore situated a short distance anterior 

 to the ventral setae bundles. 



The reproductive organs agree closely with what is known of other 

 members of the genus. A pair of testes suspended from the posterior 

 surface of the septum ^ fill not only the coelome of X, but large ante- 

 rior and posterior sperm sacs. The former is a short, wide, nearly 

 spherical diverticulum from the septum -^ which arises dorsal to the 

 intestine and projects forward when fully developed to the septum ^". 

 The posterior sac is much longer and, arising from the septum ^ above 

 the intestine, accompanies, but usually does not enter, the ovisac to 

 about somite XIII or XIV. In young worms there are two, but later 

 one disappears. Before maturity the cavity of the functional one is 

 closed by a transverse diaphragm which prevents the vascular arch 

 from entering more than a short distance. 



The large sperm funnels rest on the floor of X against the posterior 

 septum, which is perforated on each side of the nerve cord by the short 

 vasa deferentia, which then bend laterally and each expands into a 

 slightly enlarged region covered completely by a continuous layer of 

 rather small prostate gland cells. This region — the sperm reservoir — 

 bends upward around the intestine, and at the highest point passes into 

 a short ductus ejaculatorius free from glands and opening into the sum- 

 mit of the fusiform penis sac. The latter is provided with a very deep 

 epithelium thrown into rugous folds and relatively thin muscular 

 layers ; but there is no trace of a penis. The atria of the two sides open 

 into the lateral portions of the summit of an eversible median bursa, 

 which probably acts to some extent as a substitute for the penis (fig. 1). 



Ovaries occupy a position in XI relatively similar to that of the tes- 

 tes in X, and are provided with a median dorsal ovisac which, arising 

 from the septum ^^^ above the intestine, reaches to XVI or beyond. 

 In addition to the ova it receives a vascular network, usually from the 



