AN OLIGOCH.^TE WORM. .315 



We now come to some gland-like bodies which are pr-esent in 

 the clitellar region, and which I have not seen described before 

 (PI. XLIX. fig. 20). These bodies protrude into the body-cavity 

 in the ventral region of segment 12 on both sides of the male 

 openings. They are continuous with the epidermis, which in the 

 ventral region is composed of true epidermal cells, as the clitellar 

 epithelium does not extend over the ventral region. These 

 bodies are usually solid and composed of a few cells ; they are oval 

 in shape and the cells have prominent nuclei. I have occasionally 

 seen signs of slit-like cavities in them, but even then there has 

 been nothing appi'oaching a duct to the exterior. One can see 

 quite clearly that the cells forming these glands are continuous 

 with the epidermal cells, and they have evidently been formed as 

 impittings from the epidermis. The muscular systein in this 

 region is also slightly modified. Suri-ounding these glands ai-e 

 strong muscles, which are continued obliquely across the body- 

 caAdty to the lateral wall. These oblique muscles are not found 

 anywhere else, except in the region of these glands. I think 

 the most probable solution of the function of these glands is tha,t 

 they form some kind of secretion which helps to make the worms 

 adhere together closely during copulation. 



Male Opening. — The actual male opening is worthy of note. The 

 sperm-duct ends in a peculiar chitinous-like thickening (PI. XLIX. 

 fig. 21). This penis-like thickening of the sperm -duct opens to 

 the exterior in a groove. It does not pass through the so-called 

 penial bulb, but only skirts the edge of it. The penial bulb 

 (fig. 21) has every appearance of being simply one of these ventral 

 clitellar glands just described, but it is always rather bigger. 

 The cells composing it ai-e continuous with the epidermis, and it 

 has a very strong muscular coat. 



Sperm-sacs (Vesiculae Seminal es). — Beddard, in his ' Mono- 

 graph of the Oligochseta,' says: " In only one family of Oligochpetes 

 are the sperm-sacs nearly always absent ; this family is the 

 Enchytrteidfe. The genus Mesenchy trams, however, has paired 

 sperm-sacs which originate from the septum bounding posteriorly 

 the segment in which the male gonads lie." 



In E. pelluddus there are two large sacs filling up almost the 

 whole of the body-cavity in segments 10 and 11. These sacs ai-e 

 filled with sperm mother-cells and masses of spermatozoa in 

 various stages of development. Since 'sperm-sacs' is the name 

 given to sacs in which the sperm undergoes most of the stages of 

 its development, then these sacs in E. jjellucidus are undoubtedly 

 sperm-sacs, and not testes. As to the true testes, I cannot say 

 that I have ever seen them, but the following may have some 

 reference to them. 



In certain Enchytrfeids which are not quite sexually mature, 

 i. e. when the ovaries and sperm-funnels are small, I have noticed 

 a peculiar rosette of small cells in the anterior end of each sperm- 

 sac. This mass of cells, when seen in the living animal, is of a 

 definite golden-brow^n colour (PL XLYIII. fig. 18). 



21* 



