206 



the oral aperture. The following are the chief types of spicules: (1) Long, 

 slender, curved, spiny needles ; (2) Irregular forms ; (3) Short, thick, smooth, 

 conical needles, giving off root-like processes with rugose warts ; the number 

 of these varies considerably, very few exhibiting foliaceous expansions. The 

 colour of the spicules is pale yellow. The colour of the specimen is also pale 

 yellow, but the axis showing through makes it appear darker. This species 

 belongs to the smooth-needled section. 



Echinomuricea reticulata, n. sp. 

 Plate I. fig. 9 ; Plate VIII. fig. 6. 



Representing this species are two magnificent specimens measuring 200 

 mm. in length by 100 mm. in breadth, and 180 mm. in length by 110 mm. in 

 breadth respectively. Both are branched in one plane and bear a disc of 

 attachment. 



In the larger colony the stem measures 2'5 mm. at the base and tapers gradu- 

 ally to rS mm. near the tip. It is straight throughout its entire length and 

 bears branches which arise perpendicularly at intervals varying from 3 mm. to 

 8 mm. The first jjair, of which the lowest measures 140 mm. in length, are 

 directed upwards, the remainder continuing in their original course. Secondary 

 brandies are given off in the same peri)endicular manner. The diameter of 

 the branches is almost uniform throughout. There is abundant anastomosis ; 

 the whole colony forms an open network with almost rectangular meshes. 

 Some of the secondary branches extend almost as high as the main stem, 

 generally anastomosing but sometimes simply overlapping. 



The coenenchyma when viewed with a low power presents a very thorny 

 appearance which is due to the projecting ends of long spicules. It is very 

 thick, especially in the branches where it attains as much as 1 mm. The 

 spicules are densely packed and give it a very gritty structure. The general 

 colour is a light brown. 



The axis is horny, thick near the base, but very slender and flexible in 

 the branches. It is composed of interlocking strands and is very soft, present- 

 ing a ragged, glistening appearance. The colour is brown at the base but horny- 

 yellow in the branches. 



The polyps stand jjerpendicularly from the stem and branches and are 

 disposed closely over the whole cffinenchyma. The verrucoi are cylindrical, 

 truncated terminally, and measure 0'5 mm. in height and 1 mm. in diameter. 

 They are very spinose in appearance, the points of the spicules projecting 

 upwards and outwards, imbricating but not overlapping, the topmost layer 

 projecting beyond the circular opening. The great number of the verruca? and 

 the nature and method of arrangement of the spicules give the colony a char- 



