BRITISH MARINE TURBELLARIA. 473 



to Bohmig (57, p. 365), lies close to the brain. In compression 

 preparations it is driven posteriorly (PI. XLI, fig. 30). The 

 developing ova lie at the sides of the gut. The yolk-glands 

 are paired, large, lobed organs, more or less enclosing the 

 intestine and uniting behind the pharynx. 



Habitat. — In tide-pools among corallines, Port Erin, Isle 

 of Man (F. W. G.). 



Distribution. — Trieste (v. Graff and Bohmig). 



33. Plagiostoma elongatum, n. sp. 



Length 2 mm. Body cylindrical, stout,, elongate, rounded 

 in front, tapering rather suddenly posteriorly. Colour opaque 

 white. Epidermis provided with cilia, which are longer 

 anteriorly than elsewhere, and between which stiff flagella 

 occur. Narrow oblong rhabdites are thickly scattered over 

 the surface. They are homogeneous and highly refractive. 

 The musculature is strongly developed, and this fact, combined 

 with the opacity of the other organs, renders it a matter of 

 difficulty to examine this species by compression. The mouth 

 is subterminal. Pharynx large, barrel-shaped when at rest, 

 situated behind the brain. It is very muscular, and can extend 

 under and in front of the brain towards the mouth. The 

 intestine is large, corresponding generally to the form of the 

 body, slightly hollowed in front to receive the base of the 

 pharynx. Two large irregular black eyes unite by strands of 

 pigment across the brain. The genital pore is close to the 

 hinder end. The male organs were not thoroughly developed 

 in either of my two specimens, and the form of the mature 

 spermatozoa remains unknown. The germaria lie at the 

 sides of the posterior third of the body. The yolk-glands 

 form narrow lobed masses at the sides of the gut, extending 

 as far forward as the base of the pharynx. 



Habitat. — From coarse sand at the bases of Corallina 

 officinalis, Plymouth (F.W. G.). 



VOL. XXXIV, PAKT IV. NEW SEE. I I 



