lOG MAKIXF, BIOLOGY OF I'HE SUDANESE RED SEA. 



rod, but amongst the red spindlos are some with intermediate light-pink 

 shades. 



Their distinctive feature lies in the remarkably fine serration of the edges 

 of the spindles. This is a constant feature no matter what their dimensions 

 or colour may be. 



The lower cortex contains markedly spinose irregular bodies, often some- 

 what star-shaped, very spinose spindles, spinose clubs, spinose triradiates, 

 spinose bicuspids. 



The following measurements were taken of length and breadtli in milli- 

 metres : — 



Spinose spindles : 1 X 01 ; 0-75 x O'l : 0-4 x 0-12 ; 0-33 x O'l : 0-3 x Oil: 



0-25 X 0-1; 0-23 X 0-075. 

 Spinose triradiates : 0'5 ; 0'33 ; 03 = length of the three arms. 

 Spinose bicusjiids : 0"75x0'l. 

 Spinose clubs : 0-18 x 0-13. 



The canal-walls in every specimen are without spicules. 



The colour of the colonies in s(iirit varies somewhat, the colour depending 

 on that of the spicules. Where the spicules are red, the colony is reddish ; 

 where there ai'e a considerable number of white or light yellow spicules, the 

 colony is proportionately lighter in tint. 



Locality. — From :i muddy bottom, at a depth of 12 fathoms, Mersa Abu 

 Hamama, Sudan. 



Order III. PSEUDAXONIA, G. von Koch. 

 Melitodes coccixea (Ellis) ( = Isis coccinea, Ellis). (Plate 6. figs. 1 & 2.) 



The collection includes numerous specimens which are referable to Ellis's 

 Isis coccinea. From Ellis's figure and description there can be almost no 

 doubt that he referred to forms like the present specimens, which must, 

 however, be referred to the genus Melitodes. 



The specimens are of a brilliant crimson or scarlet colour, and there is 

 one yellow fragment. The most frequent mode of branching is that figured 

 by Ellis, — a broad fan, with dichotomous branches almost all in one plane, and 

 without anastomosis. In other specimens, however, the branches do not spread 

 out in a broad fan, and anastomosis is frequent. The colonies stand erect, 

 reaching a height of 4 cm. and a breadth of 2-4 cm. In some cases colonies 

 grew so close to one another that their bases formed a continuous sheet. 

 Solitary colonies show most clearly the typical fan-like form. 



The internodcs, which curve slightly in different planes, vary in lencrtb 

 from 5-10 mm. The nodes are very short, 1-2 mm., and are not distinctly 

 marked in the intact colonies. On the thinner twigs the verrucse are mostly 

 along the edges, and a somewhat flattened appearance thus results. On the 



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