VerrilL] 392 [AprU 7, 



MADREPORAEIA. 



AsTEOPSAMMiA Verrill, gen. nov. 



Corallum massive, consisting of Astrsea-like coralUtes, united quite 

 to their summits by an abundant, very porous coenencliyma. Walls 

 scarcely distinct from the ccEnencliyma, very porous. Septa in four 

 cycles, with some members of a fifth, those of the fourth uniting to 

 those of the third. Columella usually well developed, composed of 

 loose, convoluted and twisted lamellse and trabicute. Cells at times 

 shallow, the interseptal sjiaces cut off below by thin transverse septa, 

 which often nearly coincide in all the chambers. Budding chiefly 

 marginal and interstitial. 



This genus is very remarkable for it^ abundant coenenchyma, which 

 is quite exceptional in the family, Eupsammklce. 



Astropsammia Pedersenii Verrill, sp. nov. 



Corallum massive, convex above, covered with large, unequal, 

 round cells, which do not rise above the surface, unequally separated 

 by an abundant, very openly and coarsely porous coenenchyma, which 

 sometimes equals in thickness the diameter of the cells. Walls indis- 

 tinct; septa not projecting, rather thin, in the large cells four fully 

 developed cycles with the rudimentary ones of the fifth in about half 

 the systems. The primary and secondary septa are nearly equal, and 

 with those of the third, join the columella; those of the fourth cycle 

 unite to those of the third about half way to the columella. Colum- 

 ella large in the adult corallites, composed mostly of coarsely convo- 

 luted lamellas and spinose projections from the edges of the septa. 

 Transverse sejjta thin and distant, often closing up the chambers near 

 the surface. 



Diameter of largest specimen 3.5 inches ; height 2 ; diameter of 

 largest cells .40 to .50; of smallest .15 to .25; distance between cells 

 .15 to .30. 



La Paz, Gulf of California; Capt. J. Pedersen. 



I have dedicated this interesting species to Capt. James Pedersen, 

 whose extensive collections, made in the Gulf of California, have 

 contributed very much to our knowledge of the marine animals of 

 that region, and who has discovered many new and very remarkable 

 species. 



A young specimen about one inch in diameter has sixteen cells, the 

 largest of which are .3 in diameter, and very deep, with a rudimen- 

 tary columella. One cell appears to have divided by fissiparity. 



