BRITISH MARINE TURBELLAEIA. 479 



animal may continue to swim about in this condition. The 

 colour is variable, but usually consists of a broad band of 

 dark carmine reticular pigment on the upper surface, leaving 

 the side margins free, and continued on to the tentacles. The 

 anatomy differs in no important particulars from that of the 

 genus Plagiostoma. 



Habitat. — Among Ulva and other littoral weeds, Plymouth ; 

 Port Erin, Isle of Man (F. W. G.); Millport (v. Graff). 



Distribution. — Naples, Trieste, Messina (v. Graff), Wim- 

 mereux (Hallez), Norwegian coast (Miiller). 



43. VoRTicEROs LUTEUM, V. Graff (53). 



1852. VoRTiCEKOS PULCHELLUM, 0. Schmidt (28). 



1879. ,, „ var.LUTEtJM, Hallez (50). 



This species, established by v. Graff for the reception of a 

 large specimen (8 mm. long), is distinguished from the preceding 

 by its stouter appearance and uniform yellow colour. On 

 two occasions at Plymouth an example measuring 2"5 mm. in 

 length was taken. One was found among Bugula turbinata 

 from 7 fms., the other among littoral weeds at a low spring- 

 tide. 



Distribution. — Wimmereux (Hallez), Naples (v. Graff). 

 Subfamily Allostomin^. 



Plagiostomidse with one ventral and posterior 

 genital aperture. Two germaria and two distinct 

 vitellaria. Pharynx placed in the hinder half of 

 the body, its mouth directed posteriorly. 



This subfamily, as constituted by v. Graff, includes the 

 genera Enterostoma and Allostoma. Concerning it our 

 knowledge is in a most unsatisfactory condition. With regard 

 to the former genus we do not possess a good description of 

 any species, although these are abundant in northern and 

 southern seas. Consequently the definition given above must 



