426 G. WYNHOFF. 



species is not to be regarded as synonymous with Tetrastemma fiavida, 

 Burger. 



Head attenuated ; reddish or pale pink to white. With four minute 

 eyes. The very small cerebral organs are situated in front of the 

 brain. The central stylet and its base have nearly the same length. 

 All stylets are slender. With two accessory pouches, containing each 

 three accessory stylets. Length 4-5 cm., breadth ^ mm. 



Geographical distribution : Mediterranean, Channel coasts, Scotland. 



SuBORDO B. HOLORHYNCHOCOELOMIA, Burger. 



Body usually short ' and stout ; most species do not show any 

 tendency to coil themselves up. Proboscis at least as long as the 

 body. The proboscis sheath ends usually just in front of the anal 

 aperture, and always extends into the last third part of the body. 



I. Fam. amphipoeidae. 



Worms of a length of some centimetres, even of 10 cm. sometimes ; 

 the smaller species are very stout, and the larger are rather stout too. 

 The gonads do not alternate with the intestinal diverticula. They 

 bifurcate. The oesophageal diverticulum sends long pouches to the 

 brain. Proboscis sheath without lateral diverticula. Proboscis with 

 one central stylet and conical handle. Cerebral organs large. Nearly 

 always with many large eyes. Number of proboscis nerves vari- 

 able. 



GrENUS Amphiporus. 



Extremely contractile; in contraction the head is invisible as a rule. 

 They cannot swim. Usually numerous eyes, sometimes failing, never 

 four. One central stylet, but often many pouches, each containing a 

 few accessory stylets. The handle is always conical. Mouth and pro- 

 boscis pore join together. Proboscis sheath without pouches. Sexes 

 separate. 



1. Amphiporus lactifloreus, Mcintosh. (Mcintosh. Monogr. PI. I^ 

 Fig. 1). 



Locality : In shallow water, near the coast, and between tidemarks. 

 From all dredging grounds in the Sound, and once from a dredging at 

 the Mewstone Ledge (18-27 metres). 



A flattened, very soft nemertine of a pale pink or white colour. 

 The head is not sharply separated from the body. Cerebral organs in 

 front of the brain. A number of small eyes present on the head; 

 they are arranged in two groups on each side, " the posterior group 

 generally forming a triangle, with one eye-speck (that most remote 

 from the snout) much larger than the rest." 



