BRITISH MARINE TURRELLARIA. 459 



Testes compact. A spermotheca present. Mouth 

 ventral. Gut discontinuous in the adult, owing 

 to the development of the gonads. Copulatory 

 organ complicated, chitinous (v. GraflP, p. 315). 



Subfamily PSEUDORHYNCHINiE. 



Proboscis without sheath or muscular cone. Re- 

 tractors represented by short muscular bundles. 

 Pharynx rosulate. One genital pore. Two ger- 

 maria. Yolk-glands reticular. Testes paired, 

 rounded. 



Genus 11. — Pseudorhynchus, v. Graff. 



20. PSEUDORHYNCHUS BIFIDUS (McIntOsh). 



1875 . Mesostomum bipidum, Mcintosh (45) . 



Length 1'3 mm. Body convex dorsally, flat on the ventral 

 surface, slightly expanded towards the posterior end, which is 

 bifid. The conical anterior extremity (proboscis) is devoid of 

 cilia. Colour pale orange with darker spots, the proboscis 

 colourless. Rhabdites are well developed and of three kinds 

 (Jensen) — straight, ovoid, and needle-shaped. Strong adhesive 

 papillae occur at the bifid hinder end. Pharynx subcentral. 

 The genital pore is placed behind the middle. Testes 

 small, rounded. Vasa deferentia unite in a vesicula, 

 which opens, along with the ducts of '' granule-glands," into 

 the proximal swollen part of the penis. The distal portion is 

 muscular, and contains the copulatory organ. The latter is 

 a conical chitinous tube, the outer wall of which is produced 

 into a series of spiral ridges running from the base to the apex 

 in a screw-like manner. The usual direction appears to be 

 '^right-handed.'* von Grafi" notes an interesting *' left-handed" 

 variety. The germaria are large lateral oval sacs, placed op- 

 posite the centre, and directed forwards. The spermotheca 

 is finger-shaped with muscular walls. It contains the granular 

 secretion of a large number of glands. 



Habitat. — On half-decayed Laminaria and Ulva, Millport 



