Coloration of Echinus angulosus, A. Agass. 193 



lower halves. The tube-feet were approximately the same 

 colour as those of the red specimens. 



Grey specimen : the large spines were white or grey for 

 about two-thirds of their length and greenish in colour for 

 the lower one-third of their length. The small spiues were 

 for the greater part green, with a shorter white or grey 

 portion and a minute pink tip. The tube-feet were appa- 

 rently lighter than in the red or lilac specimens. 



Pinkish-green specimen : the large spines were pink for 

 two-thirds of the way down, the basal third was green, the 

 basal swelling of the same colour. The small spines were 

 pink on the upper third and green on the lower two-thirds. 



Pink specimen : the large spines were mainly pink, but 

 brownish at the tip and green at the base. The small spines 

 wore green for the greater part of their length, but pink near 

 the tip. 



Specimen intermediate between red and blue : the large 

 spines were bluish in their upper portions, but quite red in 

 their lower portion, and with a green basal peduncle. The 

 small spines were blue in their upper portions, but green in 

 their lower parts. The tube-feet were very similar in colour 

 to those of the other specimens. 



Greenish-grey specimen : the large spines were greenish 

 below, but grey in their upper parts ; the small spines 

 greenish. Lilac specimen, the large spines were lilac on the 

 upper portion, pale lilac below, and green at the base. The 

 small spines were lilac in the upper and larger portion, green 

 in the lower portion. 



In all specimens — blue, red, lilac, &c. — the spines seem to 

 be paler in colour round the mouth. The specimens fre- 

 quently had shells &c. attached to them. 



From the foregoing notes on the coloration of this species 

 it is obvious that Echinus angulosus cannot be regarded as a 

 sexually dimorphic form so far as its colour is concerned. 



Extraneous coloration was illustrated in one specimen, 

 part of which was of a green colour. This was due to the 

 growth of a multicellular alga on one of the interambulacral 

 areas which was devoid of large spines from tho madreporic 

 area to halfway down towards the mouth. The adjoining 

 ambulacral area, between the rows of tube- feet, was also 

 commencing to be infested by the attacks of the alga. 



In the circumstances under which I worked in South 

 Africa I had no chemical or physiological appliances, and 

 thus am not in a position to make any very definite state- 

 ments regarding the nature of the pigments; but brief 



