304 PROCEEDINGS OF THE ACADEMY OF [1888. 



ed mosaic of huge Diplorias. In so far, therefore, the Bermudas 

 differ from the greater number of coral islands, in which, as is com 

 monly stated, there is a marked deficiency in the coral growth 

 within the bounding area, and an equally marked luxuriance on the 

 crest and outer slope of the reef 



In most places the largest corals do not come nearer than a foot or 

 two feet of the surfjice of this water, the massive brain-corals rarely 

 appearing in water of less depth than rive or six feet. But in the 

 shallows off the North Rock we found Porites astra'oides almost 

 at the surface in low water, and just off the entrance to Harrington 

 Sound, on the north shore, Siderasfnea galaxea was covered by only 

 about two inches of water. The borders of Harrington Sound are 

 largely overgrown with species oflsophyllia, which likewise approach 

 to within a short distance of the surface. In the greater depths of the 

 Sound we found only Oculina, down to ten fathoms, the dredge-net 

 being frequently caught and reversed by their ramose stems ; beyond 

 ten fiithoms the dredge usually came up empty. 



The following species were obtained by us : 



Mycedium fragile, Dana. 



Two specimens. North Rock ? 

 Oculina diffusa, Lamk. 



Harrington Sound. 

 Oculina varicosa, Lesueur. 



Harrington Sound. 

 Oculina pallens, Ehrenberg. 



Harrington Sound. 



I feel satisfied that' this species is identical with the preceding, the 

 same stock bearing what might be considered to be typical repre- 

 sentatives of both forms. 



The amount of variation in the disposition of the calyces, as well 

 as in their individual shape, is very great in this genus, and I am 

 by no means sure that two or three of the other forms of Ocnlina 

 here enumerated represent anything more than varietal modifi- 

 cations. Pourtales, in his illustrations of the CQrals of the Florida 

 reefs (Mem. Mus. Comp. Zoology, VII, plates I and II) correctly 

 refers, it seems to me, both types to a single species (A. varicosa.) 



Oculina speciosa. Edwards and Ilaime. 



Harrington Sound. 

 Oculina recta, Qucleh. 



One specimen, from Harrington Sound, which agrees in the special 

 characters of the species from St. Thomas (Quelch, Challenger 



