LINEUS SANGUINEUS. 189 



1846. Borlasia octoculata, W. Thompson. Ann. Nat. Hist.,, vol. xviii, p. 388 (?) 

 1850. Nemertes octoculata, Diesing. Syst. Helm., vol. i, p. 276. 



„ „ sanguinea, Ibid. Op. cit., p. 276. 



1856. „ octoculata, Byerley. Fauna of Liverpool, p. 98. 

 1860. „ communis, Van Beneden. Recher. sur les Turb., p. 7, pi. i, f. 1 — 13. 

 1862. „ octoculata, Keferstein. Zeitsch. f. wiss. Zool., Bd. xii, p. 63, taf. 7, f. 1 and 2. 



„ „ communis, Diesing. Bevis. der Turbell., p. 302. 



„ „ octoculata, Ibid. Op. cit., p. 305. 



„ „ sanguinea, Diesing. Op. cit., p. 305. 



„ „ octoculata, Ibid. Nachtrage z. Bevis. der Turbell., p. 14. 



1865. Borlasia octoculata, Johnston. Catalogue Brit. Mus., pp. 21, 287, and 290, pi. ii b, f. 2 and 2*. 



1866. „ „ Lankester. Ann. Nat. Hist., 3rd ser., vol. xvii, p. 388. 



1867. „ „ Mcintosh. Jour. Micros. Sc. ; Trans., p. 39. 



1868. „ „ Ibid. Ann. Nat. Hist., 4th ser., vol. ii, p. 293. 



„ „ „ Ibid. Proceed. Linn. Soc, Zool., vol. x, p. 251, tab. 7. 



1869. „ „ Ibid. Trans. Boy. Soc. Edinb., vol. xxv, pt. ii, p. 374 et seq. 



Habitat. — Under stones between tide-marks; less abundant than Lineus gesserensis, but 

 having a similar range in the British Islands. 



Body. — Four to eight inches long, and about a line and a half in breadth, flattened, of nearly 

 equal diameter for some distance behind the head, and then gradually diminishing towards the 

 tail. It is always proportionally much longer and more slender than Lineus gesserensis. The 

 dorsum is crossed, sometimes at rather distant intervals, by transverse lines, which cause a dimple 

 at each side, and it is probably at these furrows that rupture so frequently occurs. 



Colour. — Various shades of red and brown. Some specimens anteriorly are of a very bright 

 red, which becomes fainter posteriorly, the caudal region being pale brown. In the dark brown 

 examples the ganglionic region (not the ganglia) is bright red, the succeeding portion of the 

 dorsum dull brownish-red, and then dark brown, the latter gradually becoming paler towards the 

 tip of the tail. The under surface is somewhat paler. 



Head. — This differs from that of the former species by being scarcely wider than the suc- 

 ceeding portion of the body. Its posterior boundary can just be distinguished dorsally by the 

 slight indentations at the termination of the cephalic fissures. The whole region is narrow, flat- 

 tened, slightly tapered towards the tip, which is pale, and furnished with a central and two 

 lateral papillae, or, as the case may be, with a notch and two lateral papillae. The eyes are placed 

 further back than in L. gesserensis, are more distinctly defined, and form a regular row on each 

 side, to the number of three or four. The lateral fissures have narrow lips, and extend 

 from the tip of the snout backwards. The mouth opens in a pale space some distance behind 

 the ganglia. 



The worm is much longer and more slender than L. gesserensis, from which it is at first 

 sight distinguished by the fine reddish coloration anteriorly. It is also a less active and restless 

 species, and is prone to seek shelter under shells and stones, or in fissures and tubes, where it 

 remains in a quiescent condition for weeks. It frequently lies coiled as a firm ball amongst the 

 debris in the vessel, or loosely on the bottom, so that when the vessel is held obliquely the speci- 

 mens roll from side to side. On account of these retiring habits it is somewhat difficult to get 

 a good view of the animal. This may, however, be accomplished by transferring ^the hidden or 

 coiled worm to another vessel of salt water, when the change of element generally causes it to 



