492 ZOOPHYTES. 



Explanate, contorto-foliaceous, near a Gemmipora in habit; folia 

 clustered into a broad clump ; thickness 1 to 1^ lines ; calicles scat- 

 tered, short subtubiform ; cells very neatly 12-rayed, a little ellip- 

 tical, the centre of the bottom a short thin line ; outer surface smooth 

 and not wrinkled. 



This species is so near a Gemmipora in habit, that, excepting its 

 twelve-rayed cells and smaller polyps, it would fall into that genus. It 

 forms one of the transitions between these groups. The clumps are a 

 foot broad and six inches high, and consist of gracefully clustered folia. 

 The calicles are all regular, and differ thus from the larger part of the 

 Manoporse ; they are about a sixteenth of an inch broad, and the cells 

 are half a line in their longest diameter. Here, as well as in nume- 

 rous other instances, the fact is pressed on the attention, that there are 

 no such groups as genera in nature. The specimen belongs to the 

 Academy of Natural Sciences of Philadelphia. 



2. MANOPORA LICHEN. (Dana.} 



M. incrustans, explanata, undata sen contorta et scepe lobata, fa" crassa. 

 Corallum caliculis tubiformibus, brevissimis sen obsokscentibus, cellis 

 6-radiatis, intermediis interdum conspicuis. 



Incrusting explanate, much contorted and uneven, often lobed, fa of an 

 inch thick. Corallum having very short or obsolescent tubiform 

 calicles ; cells 6-rayed, with the intermediate rays sometimes dis- 

 tinct. 



Tahiti, Society Islands (?). Exp. Exp. 



In the surface of the corallum, this species resembles the caliculata, 

 but it differs in being thin explanate, and in having the calicles less 

 angular, with the cells one-half smaller. The folia were not clustered 

 as in the gemmulata, and the cells are smaller and 6-rayed. 



3. MANOPORA CALICULATA. (Dana.} 

 M. glomerata, subgibbosa. margine crasso et revoluto. Corallum poro- 



