TRIBE I. ASTRjEACEA. 345 



minutely (though more neatly) denticulate; and an examination of 

 the animal may require its removal to this genus. 



The name of the genus is from the Greek ^wc. sand, and alludes 

 to the appearance of the surface. The group includes part of the 

 Thamnasteriee of Le Sauvage. 

 / 



Arrangement of the Species. 



I. Cespitose. 



*l. P. obtusangula. *2. P. plicata. 



II. Glomerate. 



*3. P. fossata. *5. P. exesa. 



*4. P. columna. 



I. Psammocorce ccspitosce. 



1. PSAMMOCORA OBTUSANGULA. (Lamarclc.) Dana. 



P. cespitosa, subhemispherica, creberrime ramosa ; ramis multilobatis, 

 flexuoso-plicatis, obtusis. Corallum oririmis conspicuis, rotundis, '" 

 latis, stellis interdum paulo impressis, nusquam seriatis. 



In subhemispherical tufts, very closely branched ; branches flexuoso- 

 plicate, many-lobed, lobes short and obtuse. Corallum with the 

 oririmes distinct, circular, $ of a line broad, stars sometimes a little 

 depressed, no where seriate. 



Indian Ocean ? Lamarck. 



This species has the habit of the Pavonia divaricata, but the surface 

 has a sanded appearance, owing to the minute scabrous denticulation 

 of the hardly distinct crowded lamellae, and the angles of the lobes are 

 rounded : the lamella? become irregular and often confluent or inter- 

 rupted between the stars. In the comparatively large and distinct 

 oririme, and the slightly depressed star, this species is very distinct 

 from the following. The branches of the clump are crowded almost to 

 contact. The stars are a line in diameter. The clump examined 

 by the author was three inches across and two and a quarter high. 



87 



