999 



PLATYHELMINTHES. 



mouth and form of body variable. Uterus slightly developed and behind 

 the genital pore. Ventral muscular system much developed. 



Fam. 1 . Leimacopsidae. Dorsal face very convex ; mouth in the anterior 

 part of body. Leimacopsis Diesiug, 2 frontal tentacles with eyes at base, 

 tropical America. 



Fam. 2. Geoplanidae. Body sub-cylindrical ; mouth almost median (except 

 Microplana and Dolichoplana). Geoplana Stimpson (with Geobia and Coeno- 

 plana) S. America, Australia, K". Zealand, etc.; Sphyrocephalus Kuhl and 

 v. Hasselt (with Bipalium}, Ceylon, India, N. Zealand, etc.; Geodesmus 

 Metschnikoff ; Rhynchodcmus Leidy, world-wide, mouth a little behind the 

 middle of body. Dolichoplana Moseley ^Philippines ; Microplana Vejdovsky. 



Fam. 3. Polycladidae. Body flattened ; mouth in posterior part of body. 

 Polycladus Blanchard. 



Order 5. POLYCLADA. 



Enteron with many branches, which ramify or anastomose. Male 

 and female openings distinct (exceptionally united in Stylochoplana, 

 Discocelis). Ovaries follicular, without vitelline glands. 



The Polyclada are marine animals. Both testes and ovaries 

 are numerous and follicular. A vitellarium is absent. The female 

 genital opening is behind the male. In some forms the young are 

 hatched out as larvae, called after their discoverer, Mliller's larvae 

 (Fig. 174). 



ACOTYLEA. 



Without suckers. Mouth in the middle of the body or behind it. Copulating 

 apparatus in the posterior half of body. Without tentacles, or Avith nuchal 

 tentacles. 



Fam. 1. Planoceridae. With nuchal tentacles ; mouth about median ; male 

 copulating apparatus directed backwards. Planocera de Blainville ; P. folium 

 Grube, Berwick Bay. Imagine Girard ; Conoceros Lang ; Styloclms Ehrb. : 

 Stylochoplana Stimps., body widened in front, attenuated behind, male and 

 female openings united, with two tentacles and eyes at their base ; St. maculata 

 Quatr. , Brit, coast. Diplonchus Stimps. 



Fam. 2. Leptoplanidae. Without tentacles ; mouth about median ; male 

 copulating apparatus directed backwards. Cryptocelis Lang, with oval, 

 consistent body, mouth median, genital openings separate, eyes small in 

 indistinct groups between the brain and front body end, and round the whole 

 edge of the body; Discocelis Ehrb., broadly oval, tolerably consistent body, 

 mouth median or in front of middle, a single genital opening, eyes in two 

 groups, one on each side of brain, and on the anterior edge of the body ; 

 Leptoplana Ehrb. (Fig. 173), body elongated, genital openings more or less re- 

 moved from hind end of body, eyes in two sometimes indistinct tentacular 

 groups, and in the brain area, small eyes on the anterior edge of body ; L. tre- 

 mellaris 0. F. M., Brit, coast. Trigonoporus Lang. 



Fam. 3. Cestoplanidae. Without tentacles, body ribbon-like. Mouth not 

 far from hind end of body. Copulating apparatus directed forwards ; eyes 

 scattered over the whole head. Cestoplana Lang. 



