TWO AQUATIC OLIGOCHiETES. 



33 



L. gotoi. Spermathecse ; from a lining specimen, 

 showing their asymmetrical position, sp — saccular 

 portions, s — septum, os — spermathecal pore, dp — 

 duct portion, int — intestine. 



The wall of the efferent 

 duct consists of five layers, 

 which are direct continua- 

 tions of those of the body 

 wall. The inner surface is 

 lined by a thin cuticle, the 

 next layer is cellular and 

 folded irregularly, the cells 

 having a dense cytoplasm 

 striated perpendicularly to- 

 the axis of the duct ; the 

 circular muscle layer is well 

 developed and the longitu- 

 dinal also pretty well ; the 

 outer peritoneal epithelium is well developed, with club-shaped, 

 nucleolated nuclei. 



The three outer layers of the duct wall are continued with 

 gradually decreasing thickness into those of the saccular portion, 

 the cuticle also become exceedingly thin and totally imperceptible, 

 so that the wall appears in this portion to consist of only two 

 layers. The inner layer consists of large columnar gland cells, 

 with a thin cell wall, a very large nucleolated nucleus and a 

 compact cytoplasm containing numerous small secretory granules, 

 especially in the distal half. This epithelium is followed by a 

 connective tissue layer containing two feebly developed layers of 

 muscular fibres : an outer one of longitudinal fibres and an inner 

 of circular. 



The spermathecal cavity is filled with fine granular contents, 

 which are the secretions of the gland cells. The spermatophores 

 are never present. Vejdovsky makes the same statement on 

 L. hoffmeisteri Clap., and the same fact has been ascertained in 

 three tubificid genera Hesperodrilus. Branchiura and Telmatodrilus. 

 5). Ovaries. I have nothing to add to the statements of 

 Hat ai except that the ovary is provided with a thin membrane. 



6). Ovisac. It is an outgrowth of septum XI/XII and ex- 

 tends posteriorly on the dorsal side of the intestine, sometimes 



