W. H. Leigh-Sharpe 
285 
upon the species which he has investigated, Johansson gives us to under¬ 
stand that it is the posterior testes, if any, that are reduced. 
Upon fixation the testes may possibly swell; at any rate they occupy 
so much of the width of the abdomen that the alimentary canal becomes 
constricted between one pair, and bulged out between successive pairs, 
and, as the canal is everywhere full of red blood corpuscles, this again 
contributes to the external appearance of reddish streaks. 
Fig. 8. Platybdella anarrhichae. The anterior portion of the animal in lateral aspect. 
A, to show the genital apertures; B, with penis extruded; C. with penis which has 
been extruded partially retracted; m.g. male genital aperture; f.g. female genital 
aperture; p. penis; b. bursa; x. opening from the ductus ejaculatorii into the 
bursa; d.e. ductus ejaculatorii; v.d. vas deferens; c.g.d. cocoon gland ducts. 
The testes are chambered, each chamber having characteristic wall 
cells from which are formed the sperm mother cells (spermatocytes). 
In no case in any specimen I have sectioned do the chambers of the 
testes contain developing spermatozoa, but only spermatocytes. On 
the other hand the enlarged portion of the vas deferens functioning as 
a vesicula seminalis (and hereinafter called such for the sake of brevity) 
contains spermatoblasts, morulae, and fully developed spermatozoa 
which have just quitted the spermblastophore. The varying stages 
thus recall those of the earthworm (Fig. 9) with two important exceptions. 
