70 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



21. Cylinclrostoma quadrioculatum, Leuck. (PL XIV. 

 figs. 35 and 36.) 



Length '5 — '75 mm. Body colourless, romided in front, 

 produced posteriorly into a long pointed "tail," beset 

 with adhesive papillae. The pharnyx and its large cylin- 

 drical sheath are long and muscular. The mouth is placed 

 just in front of the brain, '^he latter is quadrate, and 

 bears two pairs of eyes : an anterior small pair, the lenses 

 of which are directed backwards and outwards, and a 

 larger posterior pair, whose lenses face forwards and out- 

 wards. The sides of the body are occupied by a large gland, 

 which produces food-yolk throughout its anterior portion, 

 ova in the posterior. Hence it is called the germ-yolk- 

 gland. The genital aperture is combined with the mouth, 

 and through it the muscular penis containing both male 

 secretions opens to the exterior. A large spermatheca lies 

 at the hinder end of the body. 



Cylindrostoma quadrioculatum occurs m tide-pools at 

 the base of the littoral zone, near Port Erin. It is also 

 recorded from Millport, Skye, and Plymouth. 



22. Gyliiidrostoma inerme, (Hallez.) 



This species resembles the former in many points, but 

 is distinguishable from it by the following characters. The 

 form of the body is stouter, the tail shorter. The bright 

 yellow colour is due to small groups of pigment granules 

 in the epidermis. The genital organs in general correspond 

 closely to those of the foregoing species, but a spermatheca 

 is absent. This form occurs among drift seaweed in Port 

 Eiin Bay and is also found at Plymouth. 



Family — MoNOTiDiE . 



23. Monotuslineatus, 0. F. Muller, (11. XIV. fig. 39.) 

 Length 2 — 2'5 mm. Body elongated, flattened, tapering 



anteriorly, armed with strong adhesive-cells posteriorly. 



