60 — MARINE BIOLOGY OF THE SUDANESE RED SBA. 
I. The specimens differ superficially from S. hartmeyerc : 
(1) in being much more ramified and crowded colonies ; 
(2) in the absence of any trace of foliate lower branches ; 
(3) in their colour-scheme, which is due to the thick covering of 
crimson spicules. As to the colour of the living specimen, 
Mr. Crossland notes that it appeared jet-black when seen 
through a fathom or two of clear water, but when brought up 
it showed a splendid dark crimson, shading into pink on 
the stem. 
They differ more intimately in the following points : 
(1) The anthocodial spicules are arranged in 8 rows of 5-7 con- 
verging pairs ; they converge but slightly and are more or 
less longitudinal in S. hartmeyert. Moreover, the uppermost 
spicules of the double rows do not project beyond the antho- 
codia as they do in S. hartmeyert. 
(2) The tip of the main “ Stiitzbiindel ” spicule is smooth, while in 
S. hartmeyeri the same spicule is most spinose towards the 
free tip. 
(3) They ditfer in the dimensions and direction of the spicules in 
the cortex of the main branches. In S. hartmeyeri the cortex 
is densely filled with large, very thick, finely spinose spindles 
up to 5x0°5 mm. They seem from the drawing to be longi- 
tudinally arranged. In the specimens in this collection the 
spindles are for the most part arranged transversely to the 
long axis of the branches. 
The following measurements of these spindles were taken in 
length and breadth in millimetres: 2x012; 18x01; 
0°65 x 0°05. 
II. The specimens differ superficially from S. mayi : 
(1) in the absence of the rigidity and brittleness characteristic of a 
species developed in one plane. The colonies in this collection 
have a well-developed bare trunk up to 7:5 em. in length. 
In one specimen the stem divides somewhat dichotomously 
into two main divisions; in another specimen, four main 
branches take origin abruptly. From the main branches 
secondary branches arise in every plane. 
(2) The branching is more profuse and the clusters of polyps are 
much denser than in S. may. 
(3) The colour-scheme is golden yellow in S. mayz. 
They differ more intimately from S. mayi : 
(1) in the absence of a greatly developed projecting spicule at the 
end of each double row of spicules on the anthocodiee ; 
