NEMERTEANS 



251 



tudinally and transversely to a greater or less extent at different parts of the body. The 

 colour that remains is usually stronger dorsally than ventrally (Fig. 23 A). These may have 

 a long slit-like mouth and firm unprotruded lips or the mouth may be a small slit with 

 pursed lips (Figs. 23 B, D, E). (ii) Elongated uncontracted forms of very pale uniform 

 colour, much thinner than type (i) . The mouth is very large and the lips are thin, protruded 

 and distorted (Fig. 23 F). (iii) Small specimens coiled spirally with small mouths and 

 pursed lips. The colour is dark and often the same dorsally and ventrally (Fig. 23 C). 



A ■** 



o 



B 



E 1- a 



Fig. 23. F'S- 24. 



Fig. 23 . Lineus cormgatus, Mcintosh. A, preserved specimen of the large type (i) ; B, E, specimens of type (1) 

 with the mouth pursed, the former from Port Stanley, Falkland Islands; D, specimen of type (i) with the 

 mouth unpursed; C, type (iii); F, the elongated type (ii). 



Fig. 24. Lineus cormgatus, Mcintosh. A, transverse section of the rhynchodaeum near the proboscis pore; 

 B, section of the rhynchodaeum farther back than A, showing the outpushings (op), x 175. 



That these differences were not discernible in life can be judged from the fact that the 

 different types were sometimes preserved together from the same haul which suggests 

 individual reactions to the fixing fluids. In April 1927 many brownish, reddish and 

 black specimens were dredged from red algae and stones in King Edward Cove. There 

 was no apparent difference in shape, although it was noticed that the brown forms were 

 perhaps rather stouter in build than the others. The roots and worms were left outside 

 the Biological Station for the night, during which the surface water in the pan froze 

 after being mixed with snow. On the following day some of the worms had relaxed and 

 taken on the appearance of type (ii), but on killing with hot water they contracted to the 

 type (i) like the remainder of the catch. 



