3 



fairly straight and at others tortuous, and give off branchlets which tend to an alternate 

 arrangement and rebranch until branchings of the 6 lh order are sometimes attained. The front 

 and back of the branches are devoid of calyces and often show a median longitudinal ridge 

 or keel. The distance between branches varies greatly, but will average perhaps 8 mm. The 

 tips of the twigs bear a pair of nearly opposite calyces with a blunt point between them indi- 

 cating the end of the axis. Calyces regularly alternate. 



The individual calyces are quite prominent for this group, cylindrical in form and regu- 

 larly alternate in position. They are directed outward, upward and slightly forward or toward 

 the front of the colony. A typical calyx measures 1.6 mm. in height and 1.3 mm. in diameter. 

 They are often slightly longer in the distal parts of the colony. The walls show a tendency 

 to form eight longitudinal ridges or corrugations on the distal parts. The margin is eight- 

 lobed and the bases of the infolded tentacles are very prominent, forming a radiate mass, the 

 intervals between the tentacles showing as a star-like figure. The tentacle bases are heavily 

 spiculated, mostly with double heads similar to those on the calyx walls and general ccenen- 

 chyma. They encrust the dorsal surface of the tentacles well to the distal end. The ccenen- 

 chyma is rather thin and the axis is calcareous without evident lamellae of chitinous matter. 



S p i c u 1 e s. These are very characteristic and consist mainly of two forms ; i st an outer 

 layer of minute double heads, densely tuberculate ; 2 nd an inner and thicker layer of spicules 

 which differs from any others that I have seen aside from this genus. They are much larger 

 than the double heads, and bar-like in outline. The bars are somewhat narrowed at the ends 

 and have their corners rounded, although the ends are fairly square. Their surface is very 

 finely and densely tuberculate, so that the actual surface of the spicule is almost completely 

 hidden except for the median girdle which is usually sharply cut but sometimes obscured or 

 completely obliterated. Almost all of the spicules are one or the other of these two forms. 

 Rarely minute crosses are seen and very rarely minute regular spindles. 



Color. The colony in general is yellowish golden brown ; the polyps very dark brown 

 or chocolate, a most unusual color, which is quite conspicuous when the polyps are dissected 

 out. None were expanded in the specimen described. 



This species is a typical Nicella according to the original definition by GRAY, and 

 demonstrates the validity of the genus. 



In a specimen from Station 257 the calyces are more crowded and proportionally shorter, 

 and grayish in color, as if bleached. A small specimen from station 260 has the calyces much 

 more distant than in the type, and is grayish brown in color. 



Genus Ellisella Gray (modified by Studer). 



Ellisella Gray. Proceedings Zoological Society of London, 1857, P- 2 57- 



Ellisella Gray. Catalogue Lithophytes British Museum, 1870, p. 25. 



Ellisella Studer. Monatsbericht der Konigl. Akademie der Wissenschaft. zu Berlin, 1878,9.659. 



Ellisella Studer. Versuch eines Systemes der Alcyonaria, 1887, p. 68. 



Ellisella Wright and Studer. Challenger Reports, the Alcyonaria, 1889, p. LXVI. 



