38 



Fig. 22. D. andersoni. 



Dendronephthya andersoni, Henderson. 



To tliis species is referred a colony which measures 8 cm. in height and 

 about 5 cm. in greatest breadth. 



The stalk measures about 2'5 cm. in 

 length and is greatly collapsed owing to the 

 large size of the canals and the thin walls 

 between them. It is granular in appearance, 

 but just at its junction with the stem it be- 

 comes stringy. 



The polyparium is loose, of no fixed 

 shape owing to the irregular lengths of the 

 branches, and is developed in one plane. The 

 main stem gives off near its base two branches 

 on opposite sides in the same plane, and then 

 rises without any further branching to the tip 

 where it divides into two. One of the lower 

 branches is much larger than the other, thus 

 giving a lop-sided development to the poly- 

 parium. Two of the lower branches are 

 flattened, reflexed, leaf-like structures which almost surround the stem, leaving 

 only two small free spaces between their edges, below one of which arises a 

 small branch vvith cylindrical lower portion and flattened concave upper por- 

 tion, and directly above each open space there is a small flattened branch. 



The polyps are arranged in groups of three to seven, and on the edges of the 

 flattened branches they occur singly or in small groups. They are low, oval, 

 measuring about 48 mm. in height and 8 mm. in breadth, and placed on the 

 stalk (about 1 mm. long) at an obtuse angle. The spicules are arranged in eight 

 double rows in each of which there are four to five pairs of converging spicules ; 

 the uppermost pair in each row are much longer than the others and project for 

 a long distance beyond the polyp. The lower polyp-spicules average about 

 0-24 mm., the upper about 0"8 mm. in length and project for 048 mm. beyond 

 the polyp. On the aboral surface of each tentacle there are two rows of small 

 flat rod-like spicules. 



The Stutzbiindel is well developed, and contains one or two spicules which 

 measure up to o-2 mm. and project for a short distance beyond the polyp. 



Cortical spicules : (a) In the stem the spicules are large thick spindles, 

 either straight, curved or greatly bent, and bearing numerous regularly arranged 

 multituberculate warts. They average about 2-4 mm. in length and about 

 0'32 mm. in breadth. In addition there are small blunt spindles with few very 

 simple warts. 



