491 



the testes grow against the bodywall and are hence positively stereo- 

 tropic and in the other group they grow away from the wall and are 

 hence negatively stereotypic. This difference is shown in figures III 

 and IV. The testes of Pelonaia, Goniocarpa and Botryorchis are posi- 

 tively and those of Sty eia and Katatropa negatively stereotypic. In 



Fig. VII/ Stages in the formation of the testes in Goniocarpa coriacea. 1, 2 and 3. 



viewed from above (perpendicularly to body-wall) ; 4 and 5, viewed from the side. 



(1 and 2, X 40; 3, X 20; 4 and 5, X 10.) 



the former case the testes begin growth by elongating and sending out 

 lobes in the plane of the body wall (see Fig. VII, 1 and 2). In Pelonaia 

 they develop no farther. In the other two genera they continue to grow 

 and send out lobes. These grow over each other as they do over the 

 body wall and they may even grow over the ovary. They always keep 



Fig. VIII. Testes of Sty eia monter eyensis viewed from the side (X 12). 



close to the bodywall, to each other, or to the ovary. Neigh- 

 boring testes may grow together into a large mass which may rise 

 some distance up from the body wall (Fig. VII, 4 and 5). In Gonio- 

 carpa coriacea these masses remain attached to the wall by a broad 

 base (Fig. III). In G. rustica they usually move away from the wall, 



