276 THE VOYAGE OF H.M.S. CHALLENGER. 



Athorybia ocellata, n. sp. (PI. XL ; PI. XII. figs. 10-18). 



Habitat. — North Atlantic, Canary Islands (Lanzerote) ; January and February 

 1867 (Haeckel). 



Corm (PI. XI. fig. 1, lateral view; fig. 2, apical view). — The complete body of 

 the elegant corm is in the contracted state, with retracted organs, nearly spherical, 

 10 to 12 mm. in diameter. In the expanded state, with distant bracts and elongated 

 organs, it has the appearance of a rose or other double flower. The numerous palpons 

 are then protruded between the distant bracts, and the siphons and tentacles more or 

 less prominent. The colour of the entire corm is slightly roseate, the bracts somewhat 

 bluish, the float purple, the centre yellow. 



Truncus. — The common central stem is an ovate or slightly conical vesicle, 6 to 9 

 mm. in diameter. Its upper pointed part is the nectostyle, includes the pneumatocyst, 

 and is surrounded by the corona of bracts. Its broader lower part is the siphostyle, 

 and bears a corona of numerous slender palpons, and beyond these, in the central part 

 of the base, four to eight large siphons, each provided with a tentacle and surrounded 

 by two gonodendra, a male and a female. The conical top of the nectostyle (PI. XL 

 fig. 1, ib) embraces sometimes the ventral side of the retracted pneumatophore (p) like a 

 cowl, and the apex of the former is prominent over that of the latter. 



Pneumatophore (figs. l,p, and 5, lateral view; figs. 2 and 6, apical view). — The 

 pneumatosaccus, which is formed by the invaginated upper half of the conical necto- 

 style, includes an ovate or urn-shaped pneumatocyst (figs. 5, 6). Its apex is colourless, 

 surrounded by a pigment-star with eight pink lanceolate rays. Its basal part exhibits 

 eight radial pouches, separated by eight vertical septa of the pneumatophore. The 

 retracted float may be hidden completely between the bracts. 



Bracts (PL XL figs. 1,2; PL XII. figs. 14-16). — The bracts or covering scales, thirty 

 to fifty in number, form an elegant corona around the pneumatophore. They are arranged 

 in three or four circles, closely jjlaced one over the other ; these circles may be regarded 

 as parts of a symmetrical corona, bisected by the ventral series of buds. The bracts are 

 elliptical or lanceolate, 6 to 9 mm. long, 2 to 3 mm. broad, inside concave and smooth, 

 outside convex and armed with a variable number of cnidal crests, usually eight. The 

 exodermal epithelium of the outside is composed of large polygonal cells, and includes 

 near the lateral margin a number of scattered large cnidocysts (fig. 15, k), and at the 

 margin itself, as well as in the prominent ribs (fig. 16, br), patches of cnidocysts and dark 

 pigment-granules. The simple canal of the bract runs along the median line of the inner 

 concave face (fig. 14, be), and ends blindly near to its apex. The jelly-substance of the 

 bract is rather thick and firm. 



