HALOSYDNA GELATINOSA. 385 



ventral division is rather long, and has a long cone for the spine superiorly. The bristles 

 are somewhat slender, with the spinous region of varying breadth, the superior simple 

 and long, the middle and inferior broad and bifid. Dorsal cirri rather long, slender, 

 and smooth, with a slight swelling (and a dark belt) below the filiform tip. The ventral 

 cirrus does not reach the adjoining tip of the fleshy part of the foot. 



Synonyms. 



1820. Polynoe foliosa, Savigny. Syst. des Ann., p. 23. 

 1826. Polinoe „ Risso. L'Europ. Merid., 414. 



1834. Polynoe „ Audouin and Edwards. AnneL, 89. 



1835. „ gelatinosa, Sars. Beskr. og Iagtt, p. 63, Tab. 9, fig. 25. 

 1851. „ foliosa, Grube. Fam. d. Ann., 37. 



1853. Aphrodita cirrosa, Dalyell. Powers Creator, ii, 164, pi. xxiv, f. 1 and 2. 



1858. Halosydna gelatinosa, Kinberg. Freg. Eugen. Eesa, Zool., p. 19, Tab. 5, fig. 26. 



1860. Polynoe gelatinosa, Sars. Christ. Yid. Selsk. Forhandl., 1860, p. 58. 



1865. „ „ De Quatrefages. Ann., i, p. 249. 



„ Lepidonotus imbricatus, Baird. Johnston's Cat. Brit. Mns., p. 340. 

 „ Alentia gelatinosa, Mahngren. Nord. Hafs.- Annul., 81. 



1866. Halosydna {Alentia) Jeffreysii, Ray Lankester. Trans. Linn. Soc, 25, p. 377, pi. Ii, figs. 12, 19 



—21, 26, 27. 



1867. Alentia gelatinosa. Mahngren. Ann. Polychset., 14. 



1869. Halosydna gelatinosa, Mcintosh. Trans. R. S. E., 25, p. 408, pi. xv, f. 6. 



1870. Polynoe foliosa, Grrube. Archiv f. Naturges., 1870, p. 288. 



1875. Alentia gelatinosa, Ehlers. Annel. 'Porcup./ op. cit., p. 34. 



„ Halosydna gelatinosa, Mcintosh. Invert, and Fishes St. A., p. 117. 



1876. „ „ idem. Trans. Z. S., ix, p. 388. 

 1879. „ „ Tanber. Ann. Danic, 82. 

 1883. Alentia gelatinosa, Levinsen. Nord. Annul., 196. 



1886. „ „ Langerhans. Zeit. f. w. Zool., 40, p. 251, Taf. 15, f. 6. 



1888. Halosydna gelatinosa, De St. -Joseph. Ann. d. sc. nat. (7), v, p. 154, pi. vi, f. 6 — 21. 



1891. ,, {Alentia) gelatinosa, Hornell. Op. cit., 237. 



Habitat. — Everywhere distributed round British shores — from Shetland in the north 

 to the Channel Islands in the south. It is generally found under stones and in crevices, 

 in laminarian roots between tide-marks, or in the valves of old shells in deeper water. It 

 ranges also to the Scandinavian coasts, as well as to Madeira. A small specimen, 13'5 

 mm. long, is described by Ehlers (1875) from the 'Porcupine ' Expedition of 1869, from 

 the great depth of 1366 fathoms, on a bottom of fine mud. This, so far as my experience 

 goes, is a rare habitat, and no station or date is given — only the position of 54° 54' N". 

 and 10° 59' W. 



Head (Plate XXVIII, fig. 11) with the transverse exceeding the antero-posterior 

 diameter, so that it forms an ovoid. Anteriorly the prominent base of the median 

 tentacle takes origin between the lateral lobes, and thus well within the anterior margin, 

 while the bases of the lateral tentacles are continuations of the head, no peaks being 

 present. The eyes are proportionally large and prominent, and have lenses. The larger 

 anterior pair occupy the projecting lateral region ; the smaller posterior pair are situated 



