14 AKT. 8. 1. IK EDA : THREE NEW AND 



the jDreseiit species. The other view maintains their production 

 from the peritoneum at indefinite j^laces. Now, in the male of 

 the present species the question admits of a very clear solution. 

 Here the testis may he said to he definitely d<n'eloped, apparently 

 from the j^eritoneum, as a longitudinal series of small cellular 

 masses, projecting into the hody-cavity above and along the 

 ventral nerve-cord and borne on a narrow mesentery-like band. 

 The testis in its entire length extends through the posterior 

 three-eighths of the body. Fig. 16 represents, highly magnified, 

 a portion of a transverse section through about the middle of the 

 posterior half of the body. In it is seen the ventral nerve-cord 

 {v.n.) m cross-section and surrounded by the reticular connective- 

 tissue, which in its turn is delimited against the body-cavity by 

 the thin peritoneum (j^r.). In the middle above the nerve-cord 

 is seen the testis in cross-section : supported on the mesentery- 

 like band is one of a series of small spherical or ovoid bodies 

 which I take to be the sperm-cell masses in an early state of 

 development. Each such body consists of a protoplasmic ground- 

 substance, containing in the periphery numerous, small and round 

 nuclei which are j^robably to be seen in the light of spermatocyte 

 nuclei. The central part of the body usually shows a roundish 

 or oval, very faintly stained space, containing a single, likewise 

 faintly stained nucleus and often one or more vacuoles in addition. 

 I take no heed in identifying the substance of the central space 

 with the S23ermat023horic mass of the detached and floating sperm- 

 mass. Moreover, it seems to correspond to the central cell of a 

 young egg-follicle in the female. As is the case with the latter, 

 the central nucleated mass appears to undergo degeneration at a 

 later stage ; anyway, the single nucleus is no longer visible after 

 detachment of the sperm-masses, the spermatophore then contain- 



