194 F. W. GAMBLE, B.SC. 



lamellae, flexed ventrally. Colour yellow, due to the prevalence of 

 pigmented yellowish-green rods over irregular brown granules. Epi- 

 dermis, flagella, and rhabdites are similar to those of G. paradoxa. 

 Eyes two, reddish, placed on each side of the otolith. Female genital 

 pore situated at one-third the length of the body from the hinder end, 

 halfway between the latter and the pore is the male aperture. The 

 chitinous mouth-piece of the spermotheca is cylindrical, and composed 

 of a number of perforated plates placed one upon another. The 

 spermatozoa are elongate, tapering at each end, with a granular central 

 portion and clear lateral membranes. Penis cylindrical, muscular. 



Habitat. — Among Laminaria, &c, Millport (v. Graff) ; among sand 

 at base of Gorallina officinalis in tide-pools, Port Erin, Isle of Man ; 

 Plymouth (F. W. G.). 



Distribution. — Bergen (Jensen). 



The stout form and yellow colour sufficiently serve to distinguish 

 this species, which, in its anatomy, closely resembles Convoluta 

 paradoxa. 



B. RHABDOGCELA. 



Gut and parenchyma distinct. A spacious body-cavity usually present. 

 Nervous and excretory organs present. Gonads hermap hrodite (except 

 Microstoma and possibly Stenostoma). Testes usually compact, and 

 ovaries, germ-yolk-gland, or separate viiellaria and germaria may be 

 present ; in all cases surrounded by a tunica propria. Pharynx 

 present, variable. Otolith usually absent. 



Family MICROSTOMIA. 



Rhabdocoela with sexual and asexual reproduction. Female accessory 

 apparatus absent. Pharynx simple. 



Genus 5. — Microstoma, 0. Schmidt, 1848 ('Die rhabd. Turbellarien 

 d. siissen Wassers'), 



Microstomidce with separate sexes and compact testes. Body uniformly 

 ciliated, provided with " ciliated grooves " and a pre-cesophageal 

 gut-caecum. 



