118 



brella turned outside in) ; below the other there is only a single such branch. 



Above each a somewhat similar small flattened branch is found. 



So far as the specimen permits one to say, the polyps are arranged in 



small bundles of five to seven and may occur singly or in small groups on the 



edges of the flattened branches. They are 

 fairly high and round, measuring about 060 

 mm. in height and 50 mm. in breadth, 

 and are placed at a very obtuse angle on 

 stalks which average about 1 mm. in length. 

 The spicules are arranged in eight double 

 rows in each of which there are four to six 

 pairs of acutely converging spicules, the 

 uppermost pair being larger and projecting. 

 The lower spicules average about 0o2 mm. 

 in length, the iippei- about 048 mm. On 

 the aboral surface of each tentacle there 

 ^ , . seem to be two double rows of spicules, 



D. ambigua. 



one of flat bars with ragged edges, and 

 lying on the top of this a second double row of much thinner rod-shaped 

 spicules with toothed edges. 



The Stiitzbiindel is well developed, and consists of a number of spindles, 

 one or two of which usually project ; they average about 1'6 mm. in length. 



Cortical spicules : (a) In the stem and branches there are apparently two 

 series of spicules, a larger series of spindles which may reach over 6 mm. in 

 length, and a smaller series of spindles which average about 1'2 mm. in length. 

 They have simple spines. The larger spicules form a rough network or lattice- 

 work the meshes of which are filled up by the smaller spicules. 



(A) In the stalk there are simple spindles, variously branched spindles, and 

 a few irregular three-rayed forms. The spindles may have the branches near 

 one end and so appear three-rayed, or they may be given oft' near the middle 

 point of a side. The larger spindles average about 1"2 mm. in length. All are 

 cov(3red by numerous rough, blunt warts. 



Canal-wall spicules ; {(t) In the stem there are simple thick spindles with 

 few simple, inconspicuous conical spines, and a number of flat, smooth, striated 

 irregularly branched forms. 



(b) In the stalk the spicules are similar to the preceding except that there 

 are a number of more prominent Y-shaped forms and that the warts are rougher. 



Colour — Polyps and upper parts of polyp-stalks, in certain parts deep brick- 

 red ; the remaining parts, greyish-white. 



Locality : Arakan Coast, 13 fathoms. 



This species may be also classified with the Ditaricato! rigida group. 



