BRITISH MARINE TURBELLARIA. 449 



Family MICROSTOMID^. 



Rhabdocoela with sexual and asexual reproduction. 

 Female accessory apparatus absent. Pharynx 

 simple. 



Genus 5. — Microstoma, O. Schmidt, 1848 ('Die rhabd. 

 Turbellarien d. siissen Wassers'). 

 Microstomidse with separate sexes and compact 

 testes. Body uniformly ciliated, provided with 

 "ciliated grooves" and a pre-oesophageal gut- 

 caecum. 



8. Microstoma grcenlandicum, Levinsen (51). 



Length 1-75 mm. Body composed of about eight zooids, 

 in colour resembling M. lineare. Eyes absent. Ciliated 

 grooves small. Rhabdites well developed anteriorly, more 

 sparsely behind. No sexual organs were observed. 



Habitat. — Among Ulva, Plymouth Sound (F. W. G.); 

 Millport (v. Graff). 



Distribution. — Egedesminde, Greenland (Levinsen). 



I place the Plymouth specimen here, for although it does 

 not agree exactly with Levinsen's original description (the red 

 spot at the anterior end is wanting), it does agree with a form 

 described by v. Graff from Millport, and placed under this 

 species. 



Genus 6. — Alaurina, Busch (26). 

 Hermaphrodite Microstomidse, with tactile ante- 

 rior "proboscis." Usually with posterior setse; 

 paired lateral ones sometimes present. 



9. Alaurina claparedii, v. Graff. 



Length '3 mm. Anterior end modified to form a tactile 



