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7. Mesostomum sp., observed at Hampstead : p, praeganglionic region, 
showing a tendency to become muscular and proboscidiform ; 
g , nerve ganglion ; m, moutb ; n n, water- vessels. 
8. Vortex (of Scbmidt) sp., observed at Hampstead : g, nerve gan- 
glion ; m, moutb ; gn, genital orifice. 
9. Microscopic larva of a marine Turbellarian ( Alaurind ), observed 
by Claparede. 
10. Anterior portion of Poly cells cornuta, after Oscar Scbmidt: p, 
praeganglionic region ; g, nerve ganglion ; ov, ovary ; i, part of 
tbe ramifying intestine ; e e, eyes. 
11. Planaria torva (Miiller) : g, nerve ganglion ; m, moutb ; ph, 
pharynx ; ov ov, ovaries ; 1 1, testes ; df, efferent ducts ; pe, penis ; 
h, supposed spermatopborej x, uterus (P) ; va, vagina; gn, genital 
opening. 
12. Planaria lactea , showing tbe Dendroccel character of tbe intestine : 
m, moutb. 
13. Microscopic larva of a marine Dendrocoel Planarian, after Alex- 
ander Agassiz. 
14. Eurylepta vittata, a marine Dendrocoel ; nat. size. 
15. Bipalium, an eartb-planarian from Ceylon ; nat. size. 
16. Geoplana terrestris, after Duges ; nat. size. 
17. Planaria gonocephala, after Dug6s ; nat. size. 
18. Planaria tremellaris, after Duges ; nat. size. 
19. Planaria cceca, after Duges ; nat. size. 
20. Planaria cut so as to produce two beads, after Duges. 
21. Part of tbe genitalia of Poly cells nigra : m, moutb; df, seminal 
efferent ducts ; pe, penis, with prickles ; gn, genital vestibule ; 
x, supposed uterus (see fig. 11). 
