POLYPS AND CORALS. 33 



CcELASTREA TENUIS Verrill, nov. 



Corallum somewhat columnar or turbinate, flat at top, 

 attached by a narrow base : the sides are marked by lobes 

 corresponding to the marginal corallites, and striated even 

 to the base ; the ribs a little prominent^ finely echinate near 

 the cells. Cells unequal, irregularly polygonal, mostly 

 closed by a complete floor below. Walls very thin, forming 

 a zigzag line between the septa. Septa very narrow, thin, 

 finely serrate, the inner edges perpendicular, little exsert, 

 not crowded, in four cycles, the last often incomplete. Pali 

 prominent, wide, and thicker than the septa, situated before 

 all the cycles except the last. Columella not apparent ex- 

 cept in a section, where it appears very rudimentary. Dis- 

 sepiments horizontal, about a tenth of an inch apart, mostly 

 coincident, so as to form complete transverse floors. 



Height 2 inches ; diameter 3 ; the average width of 

 cells .2. 



Sandwich Islands ? Prof J. D. Dana. U. S. Expl. Exp. 



AsTREA (Favia) Hombroni Bdw. and Haime. ( ?) 



Corallum incrusting at base; the surface, where free, 

 naked and striated, rising at center into a convex, lobed 

 mass. At the margin and about the base the cells are 

 oval or circular, and separated by a space equal to their 

 own diameter, while at the top they become crowded, 

 polygonal, and intimately united by thin walls. Cells of 

 medium size, rather deeper than wide, with about 18 septa 

 in three cycles, the last incomplete in part of the systems. 

 Septa narrow, considerably exsert, acute at summit, toothed 

 with small sharp spines, a little thickened at the walls, not 

 crowded. Paliform teeth, prominent, slender, placed before 

 the two first cycles. Columella well developed, spongy. 

 Costss, where the cells are separated, thick and prominent, 

 scabrous. Exotheca compact. 



Height of coral 4 inches ; diameter about the same ; 

 width of cells .12. 



Sandwich Islands ( ?) Prof J. D. Dana. 



COMMUNICATIONS ESSEX INST. VOL. V. 5. JUNE 29, 1866. 



