APPENDIX. 289 



When fully stretched out in creeping, this worm is 2 inches long, 

 but very narrow and filiform, or rather tapering to a point pos- 

 teriorly ; it is of a yellowish colour for the greater part, but the 

 anterior extremity is a rose-red, while the apex or mouth forms a 

 dark red speck. When slightly compressed between plates of glass, 

 the intestine may frequently be seen unrolling itself from the cir- 

 cular and terminal mouth in the manner that some annelidans unroll 

 their proboscis. The worm will thus sometimes nearly disembowel 

 itself. The intestine is white, round and filiform, without any 

 appendage. 



Cephalotrix lineatus (page 19). 



" Very slender. Anterior extremity obtuse, with two black eyes on 

 the surface, near the front. Posterior extremity tapering. Colour 

 universally dark grey, with a white line down the back ; anteribr 

 extremity, wherein the eyes are seated, white. Motion smooth and 

 gliding." — ** A smaller specimen, with similar eyes, but the anterior 

 portion ruddy, I conjectured might be a young animal of the same 

 species." — Dalyell. 



Cephalotrix flustrse (page 20). 



" The body is slender, and the dark line in the centre of the ante- 

 rior extremity denotes an internal organ. The eyes are very con- 

 spicuous, and are seated just at the origin of the anterior pellucid 

 part." — Dalyell, 



Tetrastemma varicolor (page 20). 



Body 1^ inch long, soft, flattened, contractile, narrowed towards 

 the tail, of a yellowish maculated colour, with a dirty greenish in- 

 testinal line down the middle. Mouth rounded. Eyes four, placed 

 in a square form and rather distant. The maculated appearance 

 proceeds from white oviform bodies. 



Tetrastemma variegatum (page 20). 



" Towards the front of the upper surface are four black eyes, set 

 in long quadrangular arrangement : the two posterior are difficult to 

 be seen." — " This animal always ascends the side of its vessel, where 

 it uniformly establishes itself in a horizontal silken tube, close to the 

 surface of the water." — Dalyell, 



Borlasia* olivacea (page 21). 



Of a dusky olive colour, often tinted with purple in front, and 

 paler at the posterior extremity, which is more acuminated than is 



* A name given by Oken to the Linens of Sowerby, coequal therefore with the 



u 



