414 ZOOPHYTES. 



the surface, as seen under the microscope, are in much shorter series, 

 and less crowded than in thefrondens. 



The Explanaria dnerascens of Ehrenberg (op. cit. Gen. 1. sp. 2) is near the above, 

 though probably distinct. It is described as follows : " Subpedalis, varife plicata et 

 sinuosa, processibus saepius infundibuliformibus, intus sterilibus (nee extus),caliculis line- 

 aribus, semiglobosis, interstitiis gyrose asperis; animalis pallii colore nigro-fusco." " In- 

 fundibula hujus formae aperte non e gemmis sed e pallii plicis coalitis oriunda." 



GENUS II. ASTR^EOPORA. BLAINVILLE. 



GemmiporidcB glomerate, ; polypis sparsis ; coraUi caliculis obsoletis, 

 cellis profundioribus, cylindrids ; interstitiis porosis. 



Gemmiporidae, with glomerate mode of growth ; polyps scattered ; 

 calicles of corallum obsolete, cells quite deep, cylindrical ; inter- 

 stices porous. 



The Astroeoporse are massive corals with scattered cells hardly pro- 

 minent, though sometimes nearly hemispherical. The lamellae are 

 narrow as in the Gemmiporse. The texture of the corallum is porous, 

 with no traces of a lamellar texture, in which respect, as well as in 

 the deep cylindrical cells, the species are very distinct from the As- 

 traas. 



This genus contains two groups, which when the animals are studied 

 may constitute different genera. In one of them the coralla have the 

 fine porous (almost compact) texture and surface of a Gemmipora, 

 and in the other, a coarser porous texture, with a decidedly echinulate 

 surface. 



From the absence of calicles it is probable that the polyps are salient 

 when expanded. 



These species are confined to the coral-reef seas. 



The Astrseoporse were separated from the genus Astrsea of Lamarck, 

 by Blainville. 



Arrangement of the Species. 



*1. A. pulvinaria. 3. A. fungiformis. 



2. A. punctifera. *4. A. stellulata. 



