BRITISH MARINE TURBELLARIA. 475 



Uljanin (41), I find two germaria present. They lie at the 

 middle of the sides of the body. 



Habitat. — In 5 fms., anaong harbour debris, Plymouth 

 (F. W. G.). 



Distribution. — Sebastopol (Uljanin). 



36. Plagiostoma caudatum, Levinsen (51). 



Length 1-5 mm. Body when swimming cylindrical, 

 tapering from the middle posteriorly, conical in front. 

 Colour yellow, due to epidermal granules. Rhabdites few. 

 Pharynx behind the brain. Eyes large, rhomboidal; between 

 them a small mass of reticular pigment, with which, accord- 

 ing to Levinsen, the pigment-cups of the eyes are sometimes 

 connected. The genital aperture lies a short distance in 

 front of the hinder end. The seminal vesicle leads by a 

 narrow duct into the cylindrical muscular penis, surrounded 

 by a double sheath, as in PL reticulatum. 



Habitat.— In 5^ fms., Plymouth Sound (F. W. G.). 



Distribution. — Egedesminde, west coast of Greenland 

 (Levinsen). 



37. Plagiostoma vittatum (Frey v. Leuckart, 23). 



Length 1 — 2 mm. The latter size is that of individuals 

 which have just laid their cocoons, v. Graff ('Monogr.,^ p. 391) 

 states that a length of 3 ram. is reached by specimens living 

 on Lamiuaria below the surface. Jensen also (49, p. 58) finds 

 larger specimens in such localities than at the surface. Tow- 

 nettings taken near shore at Plymouth yielded small examples. 

 Body convex above, broadly rounded in front, tapering to a 

 finely pointed "tail" behind. It is well figured by van 

 Beneden (33), pi. v, figs. 1 and 2. Colour more variable 

 than in any other species of Plagiostoma. The typical 

 coloration is three transverse bands of violet reticular pig- 

 ment on a white ground ; one central, one across the head, 



