WILLIAMS: ON THE GONADS OF "THE LIMN^A. 367 



duct to either the vas deferens (if spermatozoa) or to the 

 oviduct (if ova). This hermaphrodite duct is a dead white, 

 highly convoluted tube, which passes from the ovotestis to the 

 base of the albuminiparous gland; then becoming thinner it 

 courses through that gland and receives its duct ; then, at last, 

 leaving the gland it runs as a liguliform duct — ^the common 

 generative duct — on the neural aspect of the accessory albumini- 

 parous glands to the extreme anterior extremity of the first one, 

 when it suddenly divides into two portions ; — one which sud- 

 denly enlarges to form the prostata and which is continued as the 

 vas deferens, the other which is known as the oviduct. These 

 two portions have already been described. In L. peregra the 

 penis is very long and narrowly cylindrical, and situated neurally 

 to the accessory albuminiparous gland and prostata ; the vas 

 deferens proprium is much shorter in comparison and less 

 convoluted ; the prostata lies directly under the accessory albu- 

 miniparous gland and between the oesophagus and posterior end 

 of the penis, the vas deferens commences in a depression on its 

 inferior surface, and the male portion of the common generative 

 canal opens into it on its posterior aspect ; the albuminiparous 

 gland, a curved, somewhat quadrangular mass, irregularly 

 laciniate on its inferior surface, lies transversely over the 

 stomach and intestine ; there is only one accessory albumini- 

 parous gland, it is situated hsemally to the prostata ; the 

 Swammerdamian vesicle is a thin walled sac lying immediately 

 under the dorsal integument of the body at the junction of the 

 prostoma and metastoma, anterior to the accessory albumini- 

 parous gland and dorsal to the prostata, and the proximal portion 

 of the spermatheca runs in company with the oviduct over the 

 antero-dorsal surface of the prostata; the ovotestis is situated in 

 the " Mitteldarmdriise " near the apex of the spire, and the 



cells are developed from primitive germ-cells, which at some time in the life 

 of the animal, or during the whole life of the animal, are exactly similar, 

 and which correspond to the protozoon ancestors of the metazoa. It is very- 

 suggestive that in sagitta both the ovaries and the testes are developed from 

 a single primitive germ-cell. 



