226 F. W. GAMBLE, B.SC. 



has a 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, piriform 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. 



Cylindrostomino? with united mouth and genital apertures. Pharynx 

 directed backwards, the penis forwards. The spermotheca opens into 

 the genital atrium. The germinal portions of both germ-yolk-glands 

 are fused together in the middle line dorsally. 



51. Monoophorum striatum (v. Graff). 



Length 1 mm. Body cylindrical, rounded in front, pointed behind. 

 Colour carmine to the naked eye. Under the microscope, however, it 

 is seen that the reticular pigment is well developed, leaving the 

 margins of the body and the outer sides of the eyes almost free. The 

 surface of the body has a characteristic " streaked " appearance, caused 

 by the grouping of the longitudinal muscles into bundles of four to 

 six. In the intervals small rhabdites are plentiful. The cilia are 

 very strongly developed. Bohmig has discovered that the oral and 

 genital apertures unite. The pharynx is very contractile. The 

 spermatozoa are collected in a pair of vasa deferentia and transferred 

 to the globular base of the penis, the terminal part of which is narrow 

 and cylindrical. For a more detailed account see Bohmig (57), 

 pp. 435—447. 



