Netv Species oj Earthworm. 307 



off a very fine vessel from the outer side, supplying the body wall. 

 Microscopic examinatioa of this ventral blood vessel in transverse- 

 section showed that the thickness and structure of the walls were- 

 quite peculiar. (Plate XXX. Fig. 4.) 



There is a quite definite endothelial lining, with large nucleated 

 cells, and a wall that seems to be largely composed of 'muscular 

 fibres, running mainly in a circular direc-tion. Besides these ele- 

 ments tliere are numerous very large clear nucleated cells in the- 

 walls of the vessel, and liere and there between these latter are 

 quite conspicuous spaces or holes. 



Reproductive System. 



Female Organs. — The paired ovaries are situated in the thir- 

 teenth segment and the two oviducts have very large funnel-shaped- 

 openings just below them. The ducts pass through the septum, 

 dividing segments thirteen and fourt«een, and then pass to the mid- 

 ventral line, and unite as tliey pass through the thick muscular 

 wall to open to ■ the exterior. The interior of each oviduct and 

 of the common duct is richly supplied with long cilia, the length of 

 which seems to be about equal to the radius of the passage. (Plate 

 XXVII. Fig. .3.) (Plate XXX. Figs. 1, 2, 3.) 



Male Organs. — 'There are two pairs of testes, one in each of seg- 

 ments ten and eleven. These are peculiarly small, even in a well- 

 matured specimen. The vasa deferentia correspond in number 

 with the testes, and open by very conspicuous and much folded 

 rosettes just below the testes, and then continue quite separately 

 and sliglitly embedded in the ventral muscles of the body wall to the 

 eighteentli segment. Here, still paired, they enter the muscular 

 wall of the duct from the spermiducal gland of their own side, about 

 tlie middle of its length, and run parallel with the lumen for somie- 

 little distance before they enter separately. 



Tlie structure and relation of these separate vasa deferentia 

 recalls that of the same parts in Megascolides australis. (Plate- 

 XXVII. Fig. 3.) (Plate XXXI. Figs. 1, 2, 3.) Plate XXVIII. Figs. 

 5. 9.) 



The spermathecae are paired and situated in the seventh, eighth- 

 and ninth segments, decreasing in size from behind forwards. 

 Each consists of an oval sac, with an equally long but finger-like- 

 diverticulum, arising from just below the junction of the base 

 of the sac with its stalk. In the most mature worms this process; 

 often appeared to have become lobed at the tip. (Plate XXVIII. 



17 



