16 1 THE YOYAGE- OF H.M.S. CHALEENGEE. 



manner. Anterior surface obscurely fibro-reticulate, sparsely furnished with subtubular 

 pores. Zooecia on the front of the branches, immersed or very slightly prominent, those 

 of the outer sides of the branches tubular, slightly expanded towards the orifice, which is 

 more or less elliptical, -nath an entire border often much produced on one side ; dorsal 

 surface finely sulcate with minute pores in the sulci. Ocecia dorsal, subglobular or 

 gibbous, the surface reticulate or coarsely punctured. Aperture tubular, lateral (from 

 which a very slender rib stretches across to the opposite side, Hincks). Diameter of 

 branches 0'5 to 0'6 mm., and of orifice about O'l mm. 



Hahitat.—Steitioii 320, lat. 37° 17' S., long. ^53° 52' W., 600 fathoms, green sand. 



[Arctic Seas, Lovdn ; coasts of Scandinavia, Pantoppidan, Sars, Macandrew ; Shetland, 

 Barlee ; Hebrides, Norman ; Nova Zembla ; Greenland, Liitken ; St. Georges Banks, Smitt 

 and Harger.] 



§§ b. Ocecia anterior, either wholly or in part ; dorsal surface granular or 

 finely striate. 



(3) Hornera violacea, Sars. 



Hornera violacea {forma violacea), Smitt, loc. cit., p. 404, Tab. vi. fig. 6-9 ; Sars, Geol. og. 



Zool. Jagtt Raise, Jaondj., 1862, Nyt Magaz. Nat. Vid., vol xii. p. 282; Busk, Brit. Mus. 



Cat., pt. iii. p. 18, pL xviii. figs. 1-4; Norman, Shetl. Dredg. Rep. Brit. Assoc, 1867, 



p. 310; Hincks, Brit. Mar. Polyz., i, p. 469, pL Ixvii. figs. 6-8, pi. Ixii. figs. 2, 3. 

 Pustulopara orcadensis, Bk„ Quart. Journ. Mior. Sci., 1860, vol. viii. p. 214, pi. xxxix. 



figs. 1, 2. 



Character. — Zoarium more or less of a violet colour, branched, straggling ; branches 

 short, truncate, irregularly dichotomous. Zooecia very irregularly disposed, sometimes 

 crowded into small fasciculi, usually elongated ; surface punctate (not reticulate) ; dorsal 

 surface granular, or very finely striated with minute pores, often a rib-like elevation 

 down the centre of the branch. Ooecia elongated, situated in the axils of the branches, 

 usually more towards the dorsal aspect ; surface smooth, finely punctate, with a thin 

 median costa ; orifice bilabiate near the top. Diameter of branches 0"4 to 0"7 mm., and 

 of orifice 0"12 mm. 



Habitat. — Station 151, ojff Heard Island, 75 fathoms, volcanic mud. 



[Arctic and Northern Seas, generally distributed ; Shetland.] 



§ /3. fenestrata (subgenus Retihornera). — Branches sub-parallel, connected by 



transverse tubules, so as to form an expanded frond with quadrangular^ 



fenestras. 

 Retihornera (pars), Kircbenpauer, Cat. iv. of tbe Mueeum Godeffroy, 1869; Busk, ^rit. Mus. 

 Cat., pt. liL p. 19. 



