Verrill, Notes on Radiata. 509 



Astropsammia VemiL 



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



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

 to their suiuniits by an aljundant, very ))orous ca3nenchynia. Walls 

 scarcely distinct from the c(enencliyma, very porous. Septa in four 

 cycles, with some meml)ers of a fifth, those of the fourth uniting to 

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

 loose, convoluted and twisted lamelUe and trabiculse. Cells at times 

 shallow, the interseptal spaces cut off below 1)y thin transverse septa, 

 which often coincide in all the chambers. Budding chiefly marginal 

 and interstitial. 



This genus is very remarkable for its abundant ccenenchyma, which 

 is almost exceptional in the family, ExipsammidcB. 



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 ccenenchyma, 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 sej^ta are nearly equal, and with 

 those of the third join the columella ; those of the fotu'th cycle unite 

 to those of the third about half way to the columella. Columella 

 large in the adult corallites, composed mostly of coarsely convoluted 

 lamellse and sj)inose 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 fissipaiity. 



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, whose 

 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 wa^f and very remarkable species. 



