456 F. W. GAMBLE. 



at its side. Yolk-glands unbranched, lateral. (For further 

 account with figures see Jensen (49)^ pi. ii, figs. 8 — 12.) 



Habitat. — Among algae^ Drake^s Island, Plymouth Sound 

 (F. W. G.) ; among Ulva and Fucus, Millport (v. GraflF). 



Distribution. — Bergen and Sund, West Norway (Jensen). 



16. Byrsophlebs intermedia, v. Graff. 



Resembles the former species in most characters, differing 

 in the arrangement of the genital organs. The penis is 

 elongate, cylindrical, the spiral muscular fibres surrounding 

 the united vasa deferentia. The chitinous portion is narrow, 

 funnel-shaped, its tip partly surrounded by a curved process, 

 similar to the " spur ■'Mn Macrorhynchus Nsegelii. The 

 yolk-glands are branched. 



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

 G.) J Millport (v. Graff). 



Subfamily Proxenetin^. 



Mesostomidge with one common genital aperture 

 and two germ-yolk-glands. Sperraotheca pro- 

 vided at its blind end with chitinous appendages. 

 Testes small, rounded. Copulatory organ com- 

 plicated. 



Genus 9. — Proxenetes, Jensen (49). 



17. Proxenetes flabellifer, 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 



