March, 1897. 



SOME NEW BOOKS. 



195 



to these sprightly beings is extended to include methods of preserva- 

 tion. The index, to crown all, is a thoroughly good and full one. 



The volume opens with the flatworms or Platyhelminthes, — a 

 phylum with three branches, Turbellaria, Trematoda, and Cestoda, 

 organised on a similar and very distinct plan. The Turbellaria are 

 dwelt on at some length as occupying " the lowest position in the 

 whole group of worms," and " most closely allied to that great extinct 



FjG. 2. — Polystomum integerrimum, 

 a Trematode from a frog's bladder. 

 Ventral view, x 8. dvi, ductus vitello- 

 intestinalis; eh, hooks of sucking disc ; 

 /k^ intestine (all black); m, mouth; 

 ov, ovary ; pe, penis ; ph, pharynx ; 

 sc, suckers ; te, testes ; ut, uterus with 

 eggs; vag, left vagina; vd, vas de- 

 ferens ; yd, yolk-duct ; yg, yolk-glands ; 

 ? 3 common genital aperture. 



Fig. 3. — Life history of Distomum macro- 

 stomum, a Trematode. a, tailless cercaria 

 from a Leiicochloridium, x 40; B, larva as 

 hatched from the egg, x 125 ; c, metamor- 

 phosed larva (sporocyst) that has pierced 

 intestinal wall of Snccinea ; d, actively grow- 

 ing sporocyst, or Leucochlofidinm ; go, genital 

 aperture ; int, intestine ; ms, mouth sucker ; 

 11, nervous system ; ov, ovary ; ps, ventral 

 sucker ; te, testis. 



group, from which they, the Nemertinea, Rotifera, and even the 

 Annelids" appear to have been " derived." A full description of the 

 Polyclad, Leptoplana tremellaris (fig. i), with good figures, is given; and a 

 no iess good figure of the anatomy of the Triclad, Planavialactea. The 

 division of the Trematoda into Mono- and Di-genea is retained, though 

 with a protest (p. 63). There is an excellent account of the Turbel 

 larian-like Monogenetic family, the Temnocephalidae, which has no 

 British representative. Mr. Gamble believes in the existence, 



p 2 



