310 A. EB. Verrill—The Bermuda Islands; Coral Reefs. 
Plexaurella dichotoma (Esper) Koll. Figs. 156, 157. Pl. xxxiiis, fig. 1, b. 
Plate xxxvia, figs. 1, 2, spicules. 
Gorgonia dichotoma (pars) Esper, Pflanz., Gorg., pl. xiv (right hand figure), 
1788. 
Gorgonia (Plexaura) dichotoma Dana, Zoéph., p. 667, 1846. 
Plexaura dichotoma Verrill, Bull. M. C. Z., i, p. 384, 1864. Synonymy only 
in part. 
Plexaurella dichotoma Kdélliker, Icones, p. 138, pl. xiii, fig. 7, pl. xiv, fig. 10, 
pl. xviii, fig. 1, 1865. Nutting, op. cit., 1889, pp. 113-123, pl. ii, figs. 1-17. 
Gorgonia heteropora Lamk., Hist., 1816. 
Plexaura heteropora Lamx., Polyp. Flex., p. 429, 1816. Dana, Zooph., p. 670. 
Gorgonia vermiculata (pars) Lamk., Hist., ii, p. 319, 1816; p. 497, 2d ed. 
Plexaura vermiculata Edw. and H., Corall., i, p. 156. 
? Plexaurella vermiculata Kolliker, Icones, p. 138, pl. xviii, fig. 13 (spicule 
from type). 
Eunicea anceps Duch. and Mich., Corall., p. 25, pl. iii, figs. 1, 2 (young). 
Plexaurella anceps K6ll., op. cit., p. 188, pl. xviii, fig. 14 (spicule from type).* 
This species is easily recognized by its stout, rigid, upright, blunt 
branches covered with large irregular calicles, varying in shape 
when dried from round to oval and slit-like forms, with the margins 
slightly or not at all raised (fig. 156). In life the calicles are round, 
or with 8 slight lobes. The coenenchyma is dense and very thick in 
proportion to the diameter of the axis, especially in the branchlets 
(fig. 157), and contains a great number of crowded spicula, all much 
smaller than in the two preceding species, many of them elegantly 
cruciform and strongly verrucose, while those in the outer layer are 
partly club-shaped. There are no large, fusiform internal spicules ; 
those of the innermost layer are slender, acute, small, purple spindles. 
The longitudinal ducts surround the axis uniformly on all sides and 
are rather large (fig. 157). 
The color in life is dull yellowish brown, or russet-brown. When 
dried it usually becomes dull grayish yellow, straw-color, or whitish, 
with a finely granular surface. The polyps are without spicules and 
contract completely. 
The axis at the base and in the main trunk is hard, rigid, and 
partly calcareous, in layers, but in the terminal branches it is rather 
* Dr, Kélliker regarded P. dichotoma, P. vermiculata and P. anceps as dis- 
tinct species and figured a single cross-shaped spicule of each, from specimens 
believed to be the types. But on the slides of the same, which he sent to me, 
the corresponding spicules vary to an extent more than sufficient to include his 
figures of the three forms. See pl. 36a. But P. nutans Duch. and Mich., 1860, 
of which he also sent spicules from the type, is quite distinct, having the crosses 
much more slender, with longer, more acute, and less verrucose branches. 
