38 PLATYHELMINTHES TURBELLARIA CHAP, i 



worm. 1 Geoplana typhlops, a Tasmanian species, is also blind, 

 and pursues worms, as does G. triangulata (Dendy). In Trinidad, 

 von Kennel 2 observed that land-snails (Subulinae) were the food 

 of certain Land Planarians, the name of which, however, he does 

 not state. The pharynx was employed to suck out the soft parts 

 of the snail even from the upper whorls of the shell. 



Reproduction. In Planaria lactea the numerous testes (Fig. 

 17, te) are placed both above and below the alimentary canal 

 throughout the greater part of its course. The membrane 

 of each gonad is continued into a minute vas efferens, which 

 unites with those of neighbouring testes. Two vasa deferentia 

 (v.cT) arise thus on each side, one from the posterior, the other 

 from the anterior testes of the body, and open into the vesiculae 

 seminales (v.s), which may be seen in the living animal as tortu- 

 ous whitish tubes at the sides of the pharynx (Fig. 14, A). These 

 open into the penis (Figs. 14, A; 17,J), a large pyriform organ, 

 the apex of which, when retracted, points forwards, projecting 

 into the penial cavity. When this apical portion is evaginated 

 and turned inside out, it is of considerable length, and is able to 

 pass into the long slender duct of the uterus (uf) of another 

 individual. The penial sheath (ps) is part of the genital atrium 

 (gs), which is developed as a pit from the skin, and invests the 

 end of the genital ducts, the mouth of the pit forming the common 

 genital pore (go), through which both male and female genital 

 products are emitted. 



There are two ovaries (ov) placed far forwards, between the 

 third and fourth pairs of intestinal coeca. The oviducts (ovd} lie 

 just over the lateral nerves, and have a slightly tortuous course, 

 at each outward bend receiving the duct (yo] of a yolk-gland 

 (y9\ 8 that ova and yolk are already associated when the oviducts 

 open by a short unpaired tube into the genital atrium. The 

 yolk-glands develop rapidly, 3 and when fully formed are massive 

 glands occupying the spaces between the intestinal branches and 

 the testes which are then aborting. The so-called uterus (ut} } 

 apparently at first a diverticulum of the genital atrium, expands 



1 Abhandl. d. Naturf. Oesell. zu Halle, Bd. iv. 1857, p. 33. 



2 Arb. Zool.-Zoot. Instil. Wiirzburg, Bd. v. 1882, p. 120. 



3 Woodworth (loc. cit. p. 38) 'states that in Phagocata the yolk-glands arise 

 by proliferation from two parovaria, placed just in front of the ordinary ovaries, 

 lijima, however (Zeitschr. /. wiss. Zool. Bd. xl. 1883, p. 454), regarded them as 

 derivatives of the parenchyma. 



