266 FRANK E. BEDDARD. 



Hum of the penis is like that of the general body surface, but 

 underneath the epithelium is a layer of glandular cells, which 

 are prolonged into fine processes that penetrate between the 

 cells of the epithelium. Occasionally this was very apparent," 

 owing to the fact that the cells in question were laden with 

 darkly staining granules. The structure of the lower surface 

 of the penis is, indeed, closely like that of the clitellum of 

 other earthworms. In the present species I have been quite 

 unable to discover a clitellum ; it is rather risky to assert the 

 absence of this characteristically Oligochsetous organ; for a 

 long time it was thought to be absent in Moniligaster until 

 its presence was proved by Professor Bourne; in Siphono- 

 gaster, however, the structure of the penis, as well as its large 

 size, is quite in accord with the view that it may possibly per- 

 form the function of a clitellum. This organ is, as Levinsen 

 pointed out, very vascular; one particularly large trunk (fig. 18) 

 runs along the whole length ; besides this there are two smaller 

 longitudinal vessels. All these send off branches which ramify 

 in the walls of the penis. 



The great vascularity of the organ led Levinsen to 

 regard it as in all probability performing a respiratory func- 

 tion in addition to a reproductive. This may be so, but 

 the large development of unicellular glands would surely 

 need a correspondingly rich development of the blood-capil- 

 laries. 



I should mention that the penial processes are quite solid ; 

 there is no prolongation into them of the body-cavity : they do 

 contain irregular spaces due to the lax arrangement of the 

 muscular and vascular tissues which fill up the interior ; but 

 these spaces appear to be perfectly independent of the coelom. 

 In relation to this question of coelom an important fact in the 

 structure of the penes is the presence of apparently excretory 

 tubules; these are quite conspicuous, and (fig. 19, n.) show every 

 resemblance to the nephridia ; they are contorted tubes with 

 an intra-cellular lumen. I traced them some distance into the 

 thick lower wall of the penis, and was successful in discovering 

 the actual orifice on to the exterior ; traced in the other direction 



