No. 1.] ACTINIARIA OF THE BAHAMAS. 69 
base of the polyp to form a more or less retiform tissue. This 
does not seem to be the case in the Bahama form. The endo- 
derm of the mesenteries is pigmented. 
The entire colony was of a sandy yellow color, the disc being 
darker, verging towards brown. 
Tribe CERIANTHEA. 
Actiniaria with numerous unpaired mesenteries and a single 
ventral gonidial groove; the mesenteries are longest on the 
ventral side and diminish gradually towards the dorsal aspect ; 
the two mesenteries attached to the bottom of the gonidial 
groove (the directives) are remarkably small, and are distin- 
guished in this way from the other ventral septa (Hertwig). 
I was not successful in obtaining any members of this tribe, 
but Dr. H. V. Wilson discovered several free-swimming larvz 
belonging apparently to a species of Cereanthus. 
- I wish to add a few remarks of a general nature which have 
been suggested by the studies, the results of which are given 
in the preceding pages. 
I was much struck by the resemblance which the Actiniarian 
fauna of the Bahamas presents to that of the Pacific, and its 
decided difference from that of the eastern coast of America. 
It must be granted of course that little is known regarding the 
Actinology of the Gulf of Mexico and of the Central and South 
American coasts, but on the other hand the Actinians occurring 
on the Atlantic coast of the United States as far south as 
Charleston, S. C., are well known, and the dissimilarity of the 
Bahama forms to these is very apparent. To make a generali- 
zation, we may say that the Actinian fauna of the Pacific differs 
from that of the Atlantic in the greater number of Stichodacty- 
linze and Thalassianthinz which it contains, and the number of 
forms of the former sub-tribe occurring in the Bahamas is very 
noticeable. It seems that so far as the Actiniaria are concerned 
two great areas of distribution can be defined, —the Indo-Pacific, 
including the Indian and Pacific oceans and the seas connected 
with them, such as the Red Sea; and the Atlantic, including in 
this the Mediterranean. The Caribbean region of the Atlantic 
is, however, to be separated from the Atlantic region and united 
