564 ZOOPHYTES. 



surface dead, arising from the lodgment of dirt upon it, which had 

 led to its growing laterally, without upward increase. The species 

 appears to grow in more impure waters than most others of the 

 genus. 



18. PORITES FAVOSA. (Dana.) 



P. crasso-columniformis, superfaie subgibbosa, apice truncata. Coral- 

 lum robustwn cellis profundis, majusculis, conicis ; septis acutis. 



Stout columniform, surface subgibbous, summit truncate. Corallum 

 having the cells deep, rather large, conical; septa acute and durable. 



Plate 55, fig. 4, corallum, natural size; 4 a, cells, enlarged. 



Feejee Islands. Exp. Exp. 



This species resembles the mordax in its deep conical cells (as deep 

 as their breadth), and strong acute interstices, and differs in this cha- 

 racter from either of the preceding massive species. There are seven 

 or eight cells to half an inch. The specimen in the collections is four 

 inches in height, and three by two in breadth ; it was alive throughout. 



19. PORITES CRIBRIPORA. (Dana.) ' 



P. incrustans et glomerata, margine crasso et involute, superfaie gibbo- 

 suld. Corallum robustum cellis parvuKs, punctiformibus, seu conicis ; 

 septis obtusis. 



Incrusting and glomerate, margin of the incrusting mass stout, and 

 involuted or folded under ; surface small gibbous. Corallum having 

 the cells quite small, punctiform or conical ; septa obtuse. 



Plate 55, fig. 5, corallum, natural size ; 5 a, cell, enlarged. 



Feejee Islands. Exp. Exp. 



Incrusts dead coral, with a layer one-fourth to half an inch thick. 

 The thick involuted margin and small puncture-like cells (about 

 twelve to half an inch), are important characters. It has some resem- 

 blance to Ellis's figure 4, tab. 41. 



