CEPHALOTHRIX LINEARIS. 209 



1844 Astemma rufifrons, (Ersted. Op. cit., p. 82, woodcut 13 (?) 

 Cephalothrix bioculata, Ibid. Kroyer's Nat. Tids., iv, p. 573. 



„ caeca, Ibid. Op. cit., p. 574. 



Planaria linearis, Ibid. Op. cit., p. 573. 

 Astemma rufifrons, Ibid. Op. cit., p. 574. 

 „ longum, Ibid. Op. cit., p. 574. 

 „ rufifrons, Ibid. De Region. Marin., p. 79. 

 Cephalothrix bioculata, Ibid. Op. cit., p. 79. 

 1846. Borlasia ? filiformis, Johnston. Ann. Nat. Hist., vol. xvi, p. 434, pi. 15, f. 1, a, b. 

 1850. „ rufifrons, Diesing. Syst. Helm., vol. i, p. 241. 



„ „ longa, Ibid. Op. cit., p. 241. 



„ ,, cephalothrix, Ibid. Op. cit., p. 241. 



» » filiformis, Ibid. Op. cit., p. 242. 



» „ linearis, Diesing. Syst. Helm., vol. i, p. 242. 



„ Cephalothrix (Erstedii, Ibid. Op. cit., p. 246. 

 1853. Gordius gracilis, Daly ell. Vow. Creat., vol. ii, p. 74, pi. 9, f. 8—11. 

 1859. „ „ Leuckart. Archiv f. Naturges., ii, p. 187. 



1861. Cephalothrix lineata, Claparede. Recher. Anat. sur les Ann., Turb., &c, p. 82. 



1862. Borlasia longa, Diesing. Revis. der Turbell., p. 249. 

 „ „ rufifrons, Ibid. Op. cit., p. 249. 



„ „ cephalothrix, Ibid. Op. cit., p. 250. 



„ „ filiformis, Ibid. Op. cit., p. 250. 



„ „ linearis, Ibid. Op. cit., p. 250. 



„ Cephalothrix (Erstedii, Ibid. Op. cit., p. 254. 



„ Meckelia caeca, Ibid. Op. cit., p. 286. 



„ Cephalothrix ocellata, Keferstein. Zeitsch. f. wiss. Zool., Bd. xii, p. 63, taf. 6, f. 11 — 16. 



« „ longissima, Ibid. Op. cit., p. 65, taf. 6, f. 6 — 10. 



1863. Borlasia linearis, Diesing. Nachtrage zur Revis. der Turbell., p. 5. 

 „ „ ? longissima, Ibid. Op. cit., p. 6. 



„ Ommatoplea ocellata, Ibid. Op. cit., p. 7. 



„ Gordius gracilis, Ibid. Op. cit., p. 15. 



1865. Astemma rufifrons, Johnston. Catalogue Brit. Mus., pp. 19 and 288. 

 „ „ filiformis, Ibid. Op. cit., p. 19. 



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

 „ ,, filiformis, Ibid. Op. cit., p. 388. 



„ Cephalothrix lineatus, Ibid. Op. cit., p. 388 (?) 



1867. Astemma rufifrons, Parfitt. Catalogue Nat. Hist. Devon., Annelids, p. 5. 



„ Cephalothrix filiformis, Mcintosh. Rept. Brit. Assoc, 1867, Trans. Sect., p. 92. 



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



1869. „ „ Ibid. Trans. Roy. Soc. Edinb., vol. xxv, pt. ii, p. 376 et seq. 



Habitat. — Under muddy stones between tide-marks, often in great numbers, and on 

 oysters and other shells and ascidians in the laminarian region. Ranges from Shetland to 

 the Channel Islands. 



Body. — About three or four inches long, flattened, tapering towards the snout, and much 

 more towards the tail ; most variable in appearance, now stretched to a mere thread, and again 

 shortened to a worm of some volume, or thrown into alternate dilatations and contractions. It 

 is marked along the centre by the pale streak of the proboscidian sheath. 



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