THE TURBELLARIA 



uterus rudimentary; ventral body musculature well developed (see 13,. 

 26, 47). 



FAMILY 5. LEIMACOPSIDAE. Dorsal surface very convex ; mouth pre- 

 central. Leimacopsis, Dies. FAMILY 6. GEOPLANIDAE, v. Gr. Land 

 Planarians without tentacles or suckers ; eyeless, or with many marginal 

 eyes. Geoplana, Stimpson (Fig. X. 3) ; Pelmatoplana, v. Gr. ; Choerado- 

 plana,, v. Gr. ; Polycladus, Blanch. ; Artio- 

 posthia, v. Gr. ; Geobia, Dies. FAMILY 7. 

 BIPALIIDAE. Anterior end is broadened out 

 to form a semicircular cephalic plate ; mar- 

 ginal eyes. Bipalium, Stimpson (Fig. X. 1) ; 

 Perocephalm, v. Gr. ; Placocephalus, v. Gr. ; 

 P. Jcewensis, Moseley. FAMILY 8. COTYLO- 

 PLANIDAE, v. Gr., with sucker on ventral 

 surface anteriorly, and with two spherical 

 eyes. Cotyloplana, Spencer (57, Fig. X. 4) ; 

 Artiocotylus, v. Gr. FAMILY 9. RHYXCHO- 

 DEMIDAE, v. Gr., with two spherical eyes 

 anteriorly. Platydemus, v. Gr. ; Dolicho- 

 plana, Mos. ; Rhynchodemus, Leidy ; Micro- 

 plana, Vejd. ; Amblyplana, v. Gr. ; Nema- 

 todemus, v. Gr. ; Othelosoma, Gray. 



Further Remarks upon the Tridadida. 

 The distribution of these forms on 

 land, sea and fresh water, is of great 

 interest, though it remains to be seen 

 how far Hallez's classification on this 

 basis is justified. 



In general form they are flat and 

 leaf-like, though the terrestrial species 

 are usually elongated, some attain- 

 ing a length of nine or even fourteen - 



in^ViPa "FWnecnp 1&4.1 srmpare to l.fiipalium ceres, Moseley, show- 



HlGlieb. reiUbbdt, 1O-1, appeal b to ing tne characteristic head of the 



have been the first to describe a land family, and the longitudinal colour- 



-T... *! markings so common m terrestrial 



rlananan trom Brazil. bmce that 



time they have been found in nearly 



all parts of the world (by Moseley, Dar- ^^oi^ceu! 118 ^ 1 * 13 * 116 1 



win, Dendy, etc.). The Triciads are 3. Side view of the anterior nd 



, , rr-n . , . of G. Spcnceri, Dendy, showing nu- 



CarniVOl'OUS and nocturnal. 1 heir dlS- merous eye-spots () and the row of 



tfibution seems to indicate that they C1 l ^^^yiop&a whiteiega, Spencer; 

 are ancient forms ; nevertheless, they 

 have in many respects lost their primi- s'ixcotyius putmnar, 

 tive characters, and present a greater 

 degree of complexity-' and differentia- 

 tion than do the Rhabdocoelida. The 

 majority are longer and narrower than in other orders ; the anterior 

 end is frequently eared (Planaria), or with tentacles (Leimacopsis), 



