NO. 1923. DESCRIPTIONS OF PACIFIC ALCYONARIA— NUTTING. 71 



PRIMNODENDRON SUPERBUM. new species. 

 Plate 9, figs. 2, 2a; plate 19, fig. 4. 



Colony 31 cm. lugh, flabellate in general form. The main stem 

 immediately divides into three branches, the central branch forming 

 the main part of the colony. This gives off several lateral branches 

 which, in turn, give off innumerable branchlets. These latter 

 di"^nde so as to form a small rigid tuft of ultimate twigs which together 

 form a compact flattened mass so thick as to look like certain lobate 

 heads of coral, as, for example, Pocillopora or certain flat forms. 



Each main branch gives off very numerous branches from all 

 sides, but those from the front and back are shorter than those 

 from the sides and terminate approximately on the same planes in 

 front and back of the colony. All are very closely compacted so 

 that the spaces between the twig terminations are hardly greater 

 than those occupied by the twig ends themselves. 



The calyces are rather thicldy emplanted on all sides of the twigs, 

 neither in regular whorls nor in regular longitudinal rows, but some- 

 times approaching the latter. In general there are from 4 to 6 

 such irregular rows of calyces. The calyces are rather slender 

 curved clubs about 2 mm, long and 1 mm. broad at distal ends. 

 Their openings face directly upward and their margins are orna- 

 mented by sharp points from the abaxial and lateral marginal 

 scales. The adaxial marginal scales have very minute points, or 

 none. Two or three horizontal rows of scales below the marginals 

 have similar but smaller points. The eight vertical rows of scales 

 are very plainly marked, and each scale overlaps considerably the 

 base of the one above and ends in a somewhat flaring thin margin 

 with a central point. These points decrease regularly in size from 

 the margin to base of calyx, ending before the latter is reached. 

 There are 6 or 7 scales in each abaxial, abaxial lateral and adaxial 

 lateral row, and 3 or 4 to the adaxials. 



The operculum is well developed, each scale bearing a lengthened 

 point much like those around the calyx margin. The adaxial oper- 

 cular scales are much smaller than the others, and bear no points. 



The scales in the coenenchyma are smaller than those in the calyx 

 walls, and are irregular in shape, forming a mosaic. 



Color: The colony is a light yellowish-brown and the axis is black 

 proximally, and lightens distally. 



Locality. — Station 4778; Semisopochnoi Island, right tangent S. 

 45° W., left tangent S. 12° W., about 12 miles; 43-33 fathoms. 



A second specimen from the same station is larger than the one 

 described, being 45 cm. high. 



