NO. 1923. DESCRIPTIONS OF PACIFIC ALCYONARIA— NUTTING. 17 



DENDRONEPHTHYA NIGRIPES, new species. 

 Plate 2, figs. 1, la; plate 17, fig. 4. 



A number of colonies of this form were secured. A typical one is 

 dentritic in its mode of branching and measures 3.5 cm. in height from 

 base of stem, and 2.2 cm. in diameter. The main stem or stalk is 

 terete in form, being 1 cm. in diameter at its broadest part and 

 narrowing both above and below, where it is longitudinally grooved 

 so as to resemble the body of an Umhellula. The main branches 

 are flattened, very short, and soon subdivide into several very flat, 

 leaf-like terminal twigs which bear polyps both on their edges and 

 upper surfaces. 



The root of the colony is pecuhar, being divided into numerous 

 soft, flattened, slender, ribbon-Uke processes which are almost black 

 except at their distal ends, which are an orange-brown. The whole 

 polypiferous part of the colony is very compactly arranged, so as to 

 present an almost solid mass of polyps on its surface. The canals of 

 the stem extend into the thin-walled root-like processes described 

 above. 



The individual polyp heads are borne on slender pedicels, the two 

 together measuring but 2.2 mm.; the diameter of the pedicel being 

 about 0.7 mm., and of the head 1.1 mm. 



The spicules of the "Stutzbundeln" do not project conspicuously 

 beyond the polyp head. Those in the polyp walls are arranged 

 loosely en chevron, and are strongly marked, being red on a white or 

 creamy background, and the points of the chevron appear as mar- 

 ginal projections over the tentacle bases. 



Each tentacle is provided with a pseudo-operculum much as in 

 the Muriceidse, each tentacle bearing on its dorsal surface two or 

 more long slender spindles reaching nearly to the center of the mass 

 of infolded tentacles, the whole forming a slender-rayed rosette, 

 when viewed from above. 



Spicules: These are all slender spindles with fine points over their 

 entire surface, and often bent or sinuous. The largest are found 

 on the under surfaces of the branchlets, where they attain a length 

 of 4 mm. and sometimes extend rib-Hke from the base to the polyp- 

 iferous border of the branchlet. These large spicules are inter- 

 spersed with much smaller but relatively somewhat stouter spindles. 

 The spicules of the pedicels are usually white or yellowish longitu- 

 dinal spindles, while those of the polyp heads are still smaller, and 

 pinkish in color. The tentacular spindles are colorless. 



Color: The pecuhar root filaments are dark greenish-brown, al- 

 most black. The trunk and branches are white, sometimes tinged 

 with pink. The calyces on some of the branches are white; but in 

 most of them they are pinkish, sometimes tinged ^vith yellowish. 

 48702°— Proc.N.M.vol.43— 12 2 



