36 VERRILL, SYNOPSIS OP 



Breadth of the largest specimen 3 in. ; thickness .50 ; 

 Average length of cells .25 ; depth about as much. 



Loo Choo Islands. Dr. Wm. Stimpson. 



In a vertical section the walls appeal' very compact and 

 solid, and those of adjacent cells are so closely united as to 

 leave only a few small, irregular cells between ; the endo- 

 thecal plates are very thin, strongly inclined downward 

 and inward, distant about .03 of an inch, but somewhat 

 irregular; the sides of the septa are strongly granulated; 

 columella firm, but coarsely trabicular. 



Some of the cells seem to produce submarginal buds 

 thus approaching Baryastrea. In general appearance this 

 species resembles DicJiocoenia, but the character of its den- 

 ticulate septa forbids its being placed there. 



Plesiastrea Urvillei Edw. and Haime. 



A fragment, apparently of this species, is preserved in 

 alcohol. In some of the cells there are four full cycles of 

 septa, but in most of them there are but three cycles with 

 a few of the fourth slightly developed ; some cells seem to 

 have divided by fissiparity as in Favia. The polyps, as con- 

 tracted, show a broad oval mouth within the circle of prom- 

 inent pali; and the tentacles, contracted to mere tubercles, 

 are outside of the pali. Over the surface of the coral the 

 membrane is very thin. In a section the ovaries are seen 

 to fill the spaces between the septa, down to the first trans- 

 verse dissepiments. 



Port Jackson, Australia. Dr. Wm. Stimpson. 



Leptastrea stellulata Yerrill, nov. 



Corallum convex, incrusting, with irregular prominences, 

 lower surface, where free, covered with a thin epitheca. 

 Cells large, often .25 inch, with many small ones between 

 them, which are usually considerably exsert, and arise by 

 lateral or marginal budding. Septa in four cycles, broad, 

 with truncate, nearly entire summits, but finely denticulate 

 below. The six primary septa are the largest, and thick- 



