CORALS AND CORAL MAKERS. 45 



in the annexed figure one-sixth the actual diameter. Large, com- 

 pound groups, both massive and foliaceous, are formed by- 

 budding, and the budding is always superior. There are 

 no margins to the disk in this tribe, and in the corallum of 



FCXGIA DAN^, E. & H., Rf-DICEI) TO ONE-SIXTH MNKAI.I.V; a,l>, TEETH OF UI'l'ER 

 AND LOWER MARGINS OF SEPTUM, NATURAL SIZE. 



the compound kinds no wall or partition between the adjacent 

 stars, and no walls to adjoinmg polyps, or only imperfect ones. 

 The polyps consequently coalesce throughout by their disks. 

 The simple Fungise are attached when young, and then would 

 hardly be distinguished from a simple or solitary species of the 

 Astraea tribe. 



3. Oadina tribe, or Oculinacea. — These species occur 

 eitner simple or compound, and the latter are often branched, 

 massive, or encrusting, never thin, foliaceous. Budding is 

 either superior, lateral, or basal ; never by spontaneous fission. 

 The coralla are remarkable for the solid walls and lamellae 

 of the cells ; and often for having the coenenchyma nearly or 

 quite solid. Transverse septa between the lamellae are some- 

 times wanting. The calicles are usually striated externally, 

 but seldom dentate. The polyps, moreover, are small ; and 

 very commonly they stand prominent above the corallum when 

 expanded. The Orbicella, figured on page 35, is an example 

 of one of the massive Astraea-like forms, constituting the 

 Orbicella family, or OrbicellidcE^ in the Oculina tribe. 



