78 



Colon)' flabellate in form, 12 cm. in height, 8.7 cm. in spread, and much overgrown 

 with campanularian hydroids and other forms. 1.4 cm. from its base the main stem divides 

 into three parts, one being a short branch with a single undivided branchlet ; another, the 

 central one, dividing shortly into two parts each of which gives off side branches ; a third, 

 forming the main part of the colony, is pinnately branched, the pinnae themselves sometimes 

 bearing terminal twigs. The calyces are distributed on all sides of the branches, but are quite 

 irregularly spaced. Perhaps an average distance from summit to summit would be 1.5 mm. 



The individual calyces are Verrucae, a typical one measuring .7 mm. in height and 1.2 mm. 

 in diameter at the base. Their walls are filled with imbricating oval plates which are smaller 

 and much more slender on the distal than on the proximal parts of the calyx. In general the 

 calyx spicules tend to be vertical in position. 



The coenenchyma is filled with similar oval plates which are larger than those of the 

 calyx and are often irregular in outline and more or less imbricated. All of the exposed edges 

 of spicules are minutely ctenate. The polyps are completely retractile and may be entirely 

 concealed by the indrawn calyx margin. The operculum is very delicate, and is composed of 

 slender spindles arranged in the usual manner. 



Spicules. These are mainly oval or squarish discs or plates, varying in one direction 

 to typical spindles and in the other to almost round plates. Many of them are oblong with 

 rounded corners ; w'hile others have quite an irregular outline, although they never approach 

 the irregularity of true Stachelplatten. 



Color. The colony is grayish brown, the axis dark brown and the spicules colorless. 

 Occasionally a small spicule appears to be blue in color, but this is so rare that it may be 

 due to some accidental refractive effect. 



3. P lacogorgia piilchra new species. (Plate XI, figs. 4, 4^" ; Plate XXII, fig. 4). 

 Stat. 258. Tual Anchorage, Kei Islands. 22 meters. Lithothannnion. 



Colony straggling in habit and exceedingly irregular in shape, 7.2 cm. in height and 

 about 3 cm. in width. About 8 cm. from its base the main stem breaks tip into four branches, 

 two short stubs and two long tortuous branches opposite each other and standing at right angles 

 with the first pair. Each of the tortuous branches gives off three individual straggling branchlets. 

 The main branches are round in section and about 2 mm. in diameter, e.xcept at their terminations 

 where they are turgid. 



The calyces are rather evenly distributed on all sides of the branches, where they are 

 often contiguous, but sometimes as much as 1.5 mm. apart. 



The individual calyces are very low Verrucae, about 1.2 mm. in diameter; but this point 

 is very hard to determine as the calyx wall passes insensibly into the general surface of the 

 coenenchyma of the branch. The walls and coenenchyma are filled with small, imbricating, disc- 

 like plates with ctenate edges, those around the margins forming a scalloped border to the 

 calyx. The polyps are completely retractile and are often concealed by the margin closing in 

 over them. The opercular surface is flat and sunken considerably below the margin in retraction. 



