Verrill, Rotes on Radiata. 



509 



Astropsammia Verriii 



Proceedings Boston Society of Nat. History, xii, p. 392, 1869. 



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

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

 scarcely distinct from the ccenenchyma, 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 lamellce and trabiculae. Cells at times 

 shallow, the interseptal spaces cut oif below by thin transverse septa, 

 which often coincide in all the chambers. Budding chiefly marginal 

 and interstitial. 



This genus is very remarkable for its abundant coenenchyma, which 

 is almost exceptional in the family, EiqjsammidcB. 



Astropsammia Pedersenii Verriii, loc. cit 



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

 cells, which scarcely rise above the surface, unequally separated by an 

 abundant, very openly and coarsely porous coenenchyma, which some- 

 times equals in thickness the diameter of the cells. Walls indistinct ; 

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

 cycles, with the rudimentary ones of the fifth in about half the sys- 

 tems. 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. Columella 

 large in the adult corallites, composed mostly of coarsely convoluted 

 lamellae and spinose projections from the edges of the septa. Trans- 

 verse septa thin and distant, often closing up the chambers near the 

 surface. 



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

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

 columella. One cell appears to have divided by fissiparity. 



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. 



This species was named in honor of Capt. James Pedersen, wliose 

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

 so much to our knowledge of the marine animals of that region, and 

 who has discovered many now and very remarkable species. 



