15 



The type species of this genus is Hicksonella princeps Nutting. 



Just as the two types of spicules furnish the generic distinction that is most prominent in 

 the genus Plexauroid.es, so two very different forms of spicules are here used as the diagnostic 

 features of the genus Hicksonella, which the author takes pleasure in naming after the accomplished 

 naturalist Professor Sydnev J. Hickson who has done such important work in the Alcyonaria. 



i. Hicksonella princeps new species. (Plate III, figs. i, \a\ Plate IV, fig. 10). 



Stat. 240. Banda Anchorage. 9 — 45 meters. Sand and coral. 



Stat. 315. Anchorage East of Sailus Besar, Paternoster Islands. Up to 36 meters. Coral and 

 Lithothamnion. 



Colony densely arborescent, forming a profusely branched clump 1 7 cm. in height and 

 15 cm. in diameter. Immediately above the base the colony divides into two large trunks, each 

 of which divides in an irregular manner until braaches of the seventh order are sometimes 

 attained. The larger branches tend to divide by sending off branchlets in the same plane, thus 

 forming a palmate structure of the main branch. Many of the secondary branches send off a 

 number of closely approximated branchlets from one side. The distal portions of the colony 

 consists of very numerous twigs in dense tufts, the ultimate branches being very short. The 

 diameter of the colony at base is 1.3 cm., of the main branches .5 cm. and of the ultimate 

 twigs 3 mm. Some of the larger branches are somewhat flattened, but the others are round. 

 The calyces are thickly implanted on all sides of the stem and branches. In alcoholic specimens 

 they are in the form of very low verrucse, which are much less pronounced in dried specimens. 



The individual calyces are included, small, round, with their margins but slightly elevated 

 above the level of the ccenenchyma. The openings are usually quite round, but are sometimes 

 oval. The polyp in retraction sinks far below the surface. Inside the calyx margin is a propor- 

 tionately small border with eight undulations surrounding a central aperture below which the 

 retracted tentacles lie. 



A cross section of a branch shows a thick ccenenchyma, large and regularly arranged 

 watervascular canals, and a horny axis cylinder with an exceptionally small central core of 

 white noncalcareous substance. No definite layers of spicules can be made out, although there 

 seems to be a distinct pellicle of ccenenchyma between the watervascular canals and the axis. 



Spicules. These are of two very distinct kinds. By far the more numerous are quite 

 small, short, densely tuberculated spindles, so short as to be oval in outline and entirely covered 

 with verrucae. The second type is comparatively large slender, almost smooth, bar-like or terete 

 spicules attaining a length of 1.3 mm. Often one half is quite smooth and glassy, while the 

 other is finely tuberculate, the tubercles being very small. I am unable to find any definite 

 anatomical relations of these large spicules. In some cases their blunt smooth points were seen 

 projecting outward from the calyx walls. They are sparsely and irregularly distributed. 



C o 1 o r. The colony is light buffy brown. The spicules are colorless. 



A specimen of this species labeled from Station 315 is 95 cm. in length. In the one from 

 Station 240 the large spicules are sometimes arcuate, but otherwise resemble those described above. 



