POLYPS AND COEALS. 37 



ened towards the centre of the cell. The others coalesce 

 at their inner edges. Costae much thickened, but scarcely- 

 prominent above the surface of the interstitial spaces. Tex- 

 ture very compact. 



Sandwich Islands. Yale College Museum. 



Oyphastrea ocellina Edw. and Haime. 



Astrea oceUlna Dana, Zoopli. 



This species belongs truly to Cyphastrea, where Edwards 

 and Haime have placed it with doubt. 



Sandwich Islands. Yale College Museum. 



Allopora Californica Yerrill, nov. 



Corallum encrusting at base, rising into thick, irregularly 

 lobed or palmate branches, three inches or more high, some 

 of which are two inches broad, and nearly half an inch 

 thick ; others nearly round and rapidly tapering, of about 

 the same thickness as the others. Many of the branches 

 have annelid tubes in the center, and appear to be due to 

 the encrusting habit of the coral, which covers the tubes 

 with a thickness of from an eighth to a fourth of an inch, 

 and in this way may rise into false branches. Some of the 

 branches subdivide into two or three parts near the end, 

 which spread nearly at right angles. Cells very small, .02 

 inch, quite regularly scattered over the whole surface ; dis- 

 tance between them equal to two or three times their diame- 

 ter, or from .04 to .07 of an inch. Intercellular tissue com- 

 pact, with a minutely granular surface, appearing smooth to 

 the unaided eye, but having a few minute pappilae between 

 the cells. In a longitudinal section the cells are seen to be 

 filled up below, and between them there are irregularly 

 scattered, minute, rounded cavities, caused by the superficial 

 papillae or vesicles. Septa represented commonlj by six 

 thick triangular processes which converge toward the cen- 

 ter of the cells, leaving only narrow, radiating spaces be- 

 tween them ; in other cells the number varies from five to 

 eight. The septa project slightly above the common sur- 

 face, and do not reach more than half way to the center of 



