358 J. E. Duserpen—Jamaican Actiniaria: Part I.—Zoanthee. 
polyps being raised above the general level of the ccenenchyme ; in another part 
the polyps may be quite free for a few millimetres. Again, colonies would 
be collected which became quite flat on their distal surface, due to excessive 
retraction as a result of rough handling; but, on coming to observe them later, 
the polyps had elevated the upper part of their column distinctly above the level 
of the ecenenchyme, and the whole presented a very different aspect. Such 
variations have also been noted as occurring on the same colony at one and 
the same time. ‘The dimensions, especially the height of the column and 
coeenenchyme, are also very variable, depending largely upon the irregularities 
of the incrusted rock and the presence of contiguous colonies; one side of a 
colony may be two or three times the height of another. 
The colour is so very similar in all the Jamaican forms I have examined as 
to be of little assistance. So far I have only met with various tints of yellow and 
brown; a colony which appears yellowish in the water may become brown on 
removal. ‘Transverse and longitudinal wrinklings are largely determined by the 
amount of shrinkage in preservation ; alcohol material showing more than forma- 
lin. The number of tentacles has been used by Duchassaing and Michelotti as 
an important aid in distinguishing species. Generally, this can only be of service 
where one is able to study the forms in the living condition, most colonies appear- 
ing to prefer a retracted state after removal from their natural habitat. I have 
generally found that unless much injured in removal, the polyps open out suffi- 
ciently for investigation during the first day in the laboratory, and plunging into 
formalin has fixed them in this condition. I have studied the capitular or marginal 
ridges more particularly when the polyps have been thus partially or completely 
open. In the numerous cases counted, the ridges were always found to corre- 
spond with half the total number of the tentacles, 7.e., with one cycle. 
Although varying somewhat, there is no doubt that the ridges and tentacles are 
of considerable utility for systematic purposes. How far they may be depended 
upon will be seen from the following observations made specially upon numerous 
colonies from the various Cays to test the reliability of the character. Each of 
the letters indicates a separate colony, or portion of one, and the figures the number 
of ridges counted upon the individual polyps sufficiently open for the purpose. 
Lime Cay: 
A.—15, 18, 16, 16, 15, 15, 14, 15, 14, 16, 14, 15, 14, 16, 14, 15, 14, 14, 16. 
B.—19, 20, 19, 20, 19. 
C.—20, 19, 19, 20, 20. 
D.—22, 19, 19. 
E.—14, 14, 18, 14, 14, 15, 15. 
South Cay : 
F.—14, 14, 14, 14, 14, 15, 14, 16, 14, 16. 
G.—18; 18) 18; 18, 19; 185 18) 175,19; 18) 18: 
H.—18, 18, 19, 18, 18. 
I,.—18, 19, 18, 17, 19. 
