10 BULLETIN OF THE 



AA. Branches, if present, arise from the horny joints. 



Acanella. CccuencLymu uikI caliclcd filled with l.irye I'usil'unii spicula. Calicles 

 armed. 



Lepidisis. Calicles filled with large fusiform spicula. Cocuenchyma with a 

 layer of small oblong scales. Calicles armed. 



Isidella {?). Ccciienchyma and calicles with fusiform spicula. Calicles un- 

 armed (?). 



Nejirly all the known species of this group, including the largest and most 

 luxuriant ones, are from comparatively deep water, and consequently require 

 cold, or at least cool temperatures. Several species are arctic, or inhaliit the 

 deep fishing banks off the northern coasts of Europe and America, where they 

 are bathed in the cold arctic currents. Some of the species are found at great 

 dejiths (1,000 to 1,300 fathoms), where the temperature is very low. The group 

 is well represented in the deep waters of the Caribbean Sea and Gulf of Mex- 

 ico. At least nine species, belonging to the four principal genera, were taken 

 in those waters by the "Blake" expeditions, 1877 to 1880. Among these 

 there were certainly two, and perhaps three, of our northern species. 



For the sake of comparison, I have added brief descriptions and a few figures 

 of some of the West Indian forms of Acanella and Lepidisis. 



Ceratoisis Wright. 



Keratoisis Wright, Ann. and Mag. Nat. Hist., II., 18G9, p. 427 ; III. p. 24. 

 Gray, Cat. Lith. Brit. Mas., 1870, p. 18. 



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

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

 branched species of Acanella. Indeed, it is difficult to determine to Avhich 

 genus some of the unbranched species should be referred. The calcareous 

 joints are tubular. The calicles are strongly armed with large spiniform spi- 

 cula, and the ccciienchyma also contains large fusiform spicula. 



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

 specimens of C, ornata are more than four feet high. These are found at con- 

 siderable depths, in cold water, off the coasts of Newfoundland and Nova 

 Scotia. 



Ceratoisis ornata Verrill. 



Keratoisis ornata Verrill, Amer. Jour. Sci., XVI., 1878, pp. 212, 376. 



Plate IV. Figs. 3 - 3 d. 



Coral tall (sometimes over three feet high), distantly and irregularly 

 Lranched, 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 



