273 



from the fact that it still retains its main stem and expanded disc of attach ment 

 The main stem is (5 mm. in diameter near the base, which is dilated and forms a 

 truncated cone with a maximum diameter of 12 cm. At a distance of 6 mm. 

 from the attached portion the stem divides into two almost equal branches 

 which diverge at slightly ditterent angles. In the other specimens, which are 

 more complete in many ways, the principal stem has become detached. The 

 largest of these is 180 mm. high and 120 mm. broad, and bears several 

 diverging branches slightly lai'ger than the others. 



Branching occurs on the larger and also on the secondary branches at very 

 short intervals. It is strictly confined to one plane so that the whole colony is 

 flaliellate in appearance. The branches are sub-parallel, arising nearly perpendi- 

 cularly liut mostly diverging upwards. Anastomoses are abundant giving great 

 rigidity to the colony. The axes are completely fused and the branches scarcely 

 exceed 5 mm. without becoming attached to others. Into the meshes of the 

 network so formed shoi't branches about So mm. to 4 mm. in length project, 

 and it is possible that these young branches will ultimately fuse with the others, 

 forming a denser and denser colony as growth proceeds. 



The ca?nenchyma is very thick and finely granular in appearance, being 

 densely packed with warty spicules. 



Polyps occur on all sides of the stem and branches except near the base 

 of the main stem Avhere they become sparse and finally leave a bare space. 

 The verruccC vary in size and shape, but no type is restricted to any special 

 portion of the colony. Some are truncated cones measuring 1 mm. in height, 

 others are lower and more dome-like, while some scarcely protrude beyond the 

 level of the coenenchyma. When they are closed over the retracted polyp there 

 remains a small circular opening surrounded by an eight-rayed star formed by 

 the inturned lobes of the margin. The anthocodite are very minute and are 

 completely retractile. The tentacles are colourless and when infolded are 

 guarded by eight pairs of long transparent spicules, each pair enclosing an acute 

 angle ; the points project beyond the base of the tentacles. 



The colour of the colony is chocolate-red. 



The spicules are yellow in colour and include the following types with 

 measurements in millimetres : — 



(a) Warty spindles, 008 x 0-02 ; 0075 x 003. 

 {/)) Spindles with the warts in whorls, 007 x 0-03 ; 005 x 003. 

 (r) Double-clubs, O'Oti x 004, constriction 0*02. 

 0-06 X 003, „ 0-02. 



{d) Transitions to spindle-shaped (warty), 0-08 x 0-03 ; 0-085 x 0-02. 

 (e) Warty crosses with a very distinct x-shaped marking, 0-05 x 0-05 ; 

 04 X 04. 

 35 



