BRITISH MARINE TURBELLARIA. 485 



The chief points of distinetioa are the absence of calcareous 

 bodies in the epidermis, and of a spermotheca. 



50. Cylindrostoma elongatum, Leviusen. PI. XLI, fig. 19. 



Length '6 — "8 mm. Body very elongate, narrow, cylin- 

 drical, slightly tapering and rounded in front, pointed behind. 

 An apparent groove was seen just above the level of the brain, 

 separating off the portion of the conical head in front of it. 

 Colour yellowish to the naked eye; a black spot (the intestine) 

 lies in the centre. The epidermis bears specially long cilia at 

 the extremities. Small mucus-rods are present in large 

 numbers. Glands open at the anterior end in front of the 

 brain. Mouth ventral, posterior. Pharynx attached to the 

 hinder end of the gut, barrel-shaped, its free margin crenulate. 

 The intestine hasa very small longitudinal extent, not greatly 

 exceeding the transverse diameter of the body. It contains 

 yellow-green and reddish-brown remains (chiefly diatoms). 

 Brain cuboidal, the angles rounded off, without fissures. 

 Four eyes, the posterior pair being distinctly the larger. 

 Genital aperture almost terminal, just under the anterior end. 

 Testes eight to nine in number, in front and at the sides of the 

 brain. Vasa deferentia lead to the base of the posteriorly- 

 directed, pyriform penis. Numerous glands open at this point, 

 and their secretions are arranged in a radiate way. The germ- 

 yolk-glands are bulky, and lie at the sides of the gut ; they 

 unite behind the brain. Behind and at the sides of the pharynx 

 is the ovarian portion of the gland. 



Habitat. — Among tide-pools, Wembury Bay, near Plymouth 

 (F.W.G.). 



Distribution. — Egedesminde, Greenland (Levinsen). 



Genus 22. — Monoophorum, Bohmig, 1891. 



Cylindrostominae with united mouth and genital 

 apertures. Pharynx directed backwards, the penis 

 forwards. The spermotheca opens into the genital 



