Alcyonaria G 43 



Keratoisis Wright. 



Keratoisis WRIGHT, Ann. and Mag. Nat. Hist., II, 1869, p. 427; III, p. 24. 

 GRAY, Cat. Lith. Brit. Mus., 1870, p. 18. Ceratoisis VERRILL, op. cit., 

 1883, p. 11. 



In this genus the branches are usually few and distant and arise from the 

 calcareous joints. Otherwise it agrees very closely with some of the sparingly 

 branched species of Acanella. The calcareous joints are tubular. The calicles 

 are strongly armed with large spiniform spicules, and the ccenenchyma also con- 

 tains large fusiform spicules. 



In this genus are included the largest known species of the family. Some 

 specimens of K. ornata are about four feet high. These are found at considerable 

 depths, in cold water, on the Banks off Newfoundland and Nova Scotia. 



Keratoisis ornata Verrill. Gold-banded Coral. 



Keratoisis ornata VERRILL, Amer. Jour. Sci., vol. XVI, 1878, pp. 212, 376; op. 

 cit., 1883, p. 11, pi. I, figs. 4-4b (as Ceratoisis); op. cit., 1885, p. 533. 



Plate XVI; Figs. 1-lb. Plate XVII; Figs. 4-4b. 



Coral tall; sometimes over four feet high; distantly and irregularly branched, 

 the branches spreading, often nearly at right angles, elongated, rather slender, 

 gradually tapering, giving off, in the same manner, elongated branchlets. The 

 branches and branchlets mostly arise from near the proximal end of the cal- 

 careous joints, but sometimes from the middle. The calcareous joints are 

 ivory-white, elongated, round, slightly enlarged at the ends, usually faintly and 

 often indistinctly striated longitudinally, appearing smooth to the naked eye, 

 but finely granulous under a lens; they are tubular, having a central tube equal 

 to about a third or a fourth of their total diameter. The chitinous joints are 

 usually lustrous golden yellow or bronze-color, sometimes plain brown, short, 

 scarcely longer than thick in the larger branches, about twice as long as thick 

 in the smaller ones, where they become translucent and brownish or amber- 

 color, without the metallic lustre seen in those of the larger branches. The 

 basal part is deeply divided into irregular, palmate, flattened lobes, or root-like 

 expansions, by means of which it anchors itself in the mud. 



One specimen,- preserved in alcohol, shows remarkable variations in the 

 length and form of the calicles. Over most of the branches they are very long 

 and prominent, constricted in the middle, with an expanded base and enlarged 

 summit, crowned by eight prominent spines, surrounding the incurved and nearly 

 retracted tentacles (PL XVII, fig. 4a). In this form of calicle the length is two to 

 three times the average diameter. But on other branches the calicles are only 

 prominent, sub-conical verrucas, broadest at base, with the summit narrow, and 

 the spines but little prominent (Fig. 4a) ; these are often about as broad as high. 

 Intermediate forms also occur on this specimen. The calicles are irregularly but 

 rather uniformly scattered over the whole surface, and are mostly separated by 

 spaces two or three times as great as their breadth, though some are in contact 

 at their bases. The surface of the ccenenchyma and calicles is covered with a 

 soft integument, which nearly conceals the spicules, except at the border of the 

 calicles; but they become conspicuous when dried. 



The calicles in dried specimens are usually prominent, elongated, somewhat 

 expanding toward the end, and are crowded nearly equally over the whole 

 surface; they are covered with large, conspicuous, acute spicules which form, at 

 the summit, eight sharp spinous points. (See PL XVI, fig. la). The ccenen- 

 chyma is thin, translucent, yellowish, filled with long and large fusiform, spicules. 



