BRITISH MARINE TURBELLARIA. 199 



Distribution. — Faroe Islands (Schmidt). 



This species has hitherto only been seen by Schmidt, who gave no 

 account of the genital organs. He described the form and colour, the 

 position of the pharynx, and the eyes. Excepting the difference in 

 size (Schmidt's specimens measured 1'5 mm.) I have no reason for 

 doubting the identity of my specimens with his. 



As regards the systematic position of this species, my observations 

 are not perfectly conclusive. It is possible that further investigations 

 may prove that the organ R. s. is a receptaculum seminis, and B. c. 

 a bursa copulatrix, the transverse markings I have noted being the 

 subspiral muscles of Jensen. At present, however, from the nature 

 of the protoplasm, I believe it to be an ovary, while the presence of a 

 single genital opening is evidence for a position in the genus Promesos- 

 toma, where v. Graff has already placed it doubtfully.* 



14. Promesostoma agile (Levinsen). PI. XI, fig. 14. 



Length *5 mm. Body oval, rounded posteriorly, tapering forwards 

 in front of the hinder third. Colour light red. Movements very 

 active. Eyes placed close together, triangular, the apex being formed 

 by the pigment-cup, directed inwards and backwards, the lens outwards 

 and forwards. Pharynx subcentral. Intestine reddish, occupying the 

 space between the pharynx and the lateral yolk-glands. The genital 

 aperture is placed about halfway between the pharynx and the posterior 

 end. The testes are two oval sacs behind the pharynx ; they com- 

 municate by short ducts with the penis, the base of which is spherical, 

 and contains the secretion of a granule-gland, while its distal portion 

 is produced into a long, narrow, slightly curved copulatory organ. A 

 pair of ovaries are placed at the posterior end of the body, their ducts 

 running forwards to the genital aperture. The yolk-glands are lateral 

 uniting behind the brain. A small muscular sac placed behind the 

 penis appears to be a receptaculum granulorum. 



Habitat. — Two specimens among littoral weeds, Plymouth 

 (F. W. G.). 



*A second genital pore might have easily been overlooked. If further 

 examination should demonstrate a second aperture, the species -would have to 

 be transferred to the genus Byrsophlebs. 



