344 ZOOPHYTES. 



GENUS IX. PSAMMOCORA. DANA. 



Fungidce affixce, glomeratce, aut ramose ; polypis obsolete tentaculatis, 

 non seriatis ; interstitiis interdum planulatis, scepius undique turgide 

 elevatis; itaque super fide cellis interdum excavata. Corolla porosa; 

 oririmis minutis; lamellis subtilissimis, minute arenoso^denticulatis, 

 sczpius irregularibus, alternis non minoribus. 



Attached Fungidae, glomerate or ramose ; tentacles of polyps obsolete, 

 polyps not seriate ; interstices sometimes flat, usually throughout 

 turgidly elevated, the surface, then, consisting of excavate cells. 

 Coralla porous ; oririmes minute ; lamellae very minute, often in- 

 distinct, and very minutely arenoso-denticulate, often irregular, 

 not alternately smaller. 



The large excavate cells, sometimes meandering, of many of the 

 Psammocorae, give them much the appearance of certain Astrseas, or 

 Meandrinse, yet they have properly the characteristics of the Fun- 

 gidae. The lamelke are very minute, even, and granulous, like the 

 Agariciae (though peculiar in not being entire), and the oririmes are 

 distinct though small. Moreover, the polyps are without tentacles. 

 A close examination of the animals shows that the cells arise merely 

 from the growth or enlargement of the interstitial parts, above the 

 level of the polyp-mouths. They do not correspond to the visceral 

 cavity of the animal ; for when expanded, there is no disk, as in the 

 Astrseas, rising above the bottom of the cell: the surface integument 

 follows all the excavations and ridges of the surface, precisely as in 

 the Agariciae. Unlike the Mycedise, the internal texture is quite 

 porous. There are some branching corals that have the peculiar 

 lamella? of the Psammocora?, but without excavate cells; as the 

 former character appears to be of paramount importance, they are 

 placed in this genus, rather than with the Pavonia?, which have the 

 lamella? entire, or nearly so. As in the Pavoniae, there are eighteen to 

 twenty-eight lamella? in a breadth of a quarter of an inch. 



The Astrsea galaxea is near the Psammocora? in its fine lamella?, 



