BRITISH MARINE TURBELLARIA. 201 



The chitinous portion is narrow, funnel-shaped, its tip partly 

 surrounded by a curved process, similar to the "spur" in 

 Macrorhynchus Naigelii. The yolk-glands, are branched. 



Habitat. — In tide-pools. Port Erin, Isle of Man (F. W. G.) ; Mill- 

 port (v. Graff). 



Subfamily Proxenetin.ze. 

 Mesostomida2 with one common genital aperture and two germ-yolk-glands. 

 Spermotheca provided at its blind end with chitinous appendages. 

 Testes small, rounded. Copulatory organ complicated. 



Genus 9. — Proxenetes, Jensen (49). 



17. Proxenetes flabelliper, Jensen. 



Length 1 — 1*5 mm. Body cylindrical, abruptly rounded in front, 

 narrowing posteriorly to a short "tail," colourless. Flagella are 

 everywhere present between the cilia. Long, sharply-pointed rods are 

 present in great numbers in the epidermis, forming two well-defined 

 tracks between the eyes and supplying the anterior end. Smaller rods 

 occur over the rest of the surface. The hinder end is provided with 

 adhesive cells. Pharynx large, placed in the posterior third. Between 

 it and the hinder end is the genital aperture. The large testes occupy 

 the middle of the sides of the body. The vasa defer entia are swollen 

 just before uniting at the base of the retort-shaped penis which 

 receives the secretion of grdnule-glands. The copulatory organ is a 

 complicated mechanism of chitinous pieces separating the granule- 

 secretion from the spermatozoa. The nutrient part of the germ-yoke- 

 gland extends along the sides of the body; the ovarian portion 

 develops behind the pharynx. The two oviducts unite, and the 

 common duct runs to the genital pore. Opening into the atrium, 

 close to the pore, is the large spermotheca, which is directed forwards 

 towards the pharynx, and then bends back upon itself. Its blind end 

 receives chitinous ducts conveying granule-secretion. The point of 

 connection with the genital atrium is armed with five to six triangular 

 chitinous teeth, freely hinged at their bases. A fui'ther account of 

 these structures will be found in v. Graff (pp. 277^279) and Jensen 

 (49). The above are points I have verified myself. 



