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THE VOYAGE OF H.M.S. CHALLENGER. 
alternate ramuli, every ramulus supported by a rather long cladophore, and having its 
proximal internode united to the next by a very oblique, splice-like joint. Hydrothecae 
borne both by main stem and pinnae ; those of the pinnae in distant pairs, exactly 
opposite, adnate to one another along their opposed sides, then strongly divergent, and 
terminating in an orifice with a broad cusp on each side ; apocauline wall with a strong, 
inflected fold at somewhat more than half its height from the base ; hydrothecae of main 
stem subopposite in distant pairs, with a solitary hydrotheca in the axil of every pinna ; 
those of each pair not adnate to one another by their opposed sides. 
Gonosome not present. 
Locality . — Station 36, off Bermuda ; depth, 30 fathoms. 
Desmoscyphus gracilis is a small and elegant species. It attains a height of about 
two inches, and its slender, undivided stems, with their regular, pinnately disposed 
ramuli, give to it a symmetrical and graceful habit. The pinnae are divided by distinct 
joints into well-defined, rather long internodes, each of which carries close to its distal 
end a pair of connate hydrothecae. The deep inflexion of the apocauline wall of the 
hydrotheca forms in the interior of its cavity a prominent, transverse ridge. The 
pinnae are supported on rather long cladophores, and the proximal internode, which is 
cylindrical and destitute of hydrothecae, is united to the next by a very oblique, over- 
lapping, splice-like joint, the opposed sides of these two internodes being here cut away 
to an acute point. The union between the internodes is weaker at this joint than at any 
other, and the pinna here becomes easily separated from the proximal internode, which 
remains still attached to the cladophore, its sharp, distal end giving it the appearance 
of a rigid spine. Many of the pinnae, towards the hydrorhizal end of the stem, have in 
the greater number of the specimens become detached at this joint, and the stem has 
then the appearance of being, for some distance from its base, armed on each side with 
a series of sharp spines. 
The main stem is also divided into distinct internodes by joints which are situated 
one just below every pinna. The hydrothecae of the stem are not as in the pinnae 
exactly opposite. They are subopposite, and those of each pair, instead of being adnate 
to one another as in the pinnae, are separated by a considerable interval. 
Desmoscyphus obliquus, n. sp. (PI. XXXIY. figs. 3, 3a). 
Trophosome . — Stem monosiphonic, unbranched, divided into short internodes, each 
of which sends off a pinna from alternate sides ; pinnae composed of well-defined inter- 
nodes, each carrying a pair of obliquely opposite hydrothecae. Hydrothecae of pinnae 
wide, adnate to internode for nearly their entire height, and with their free ends slightly 
divergent ; margin with a broad cusp on each side . 
