31(5 
GENUS II. PARACYATHUS (M. Edvv. & EIaime). 
Corallim simple, subturbiiiate or cylindrical, with 
an expanded base, permanently adherent. 
Columella very broad, terminated by a papillous 
surface, and formed by processes that appear to arise 
from the lower part of the inner edge of the septa. 
Palules of divers orders, forming two or more 
circles ; in general lobed at the summit, narrow, tall, 
and appearing also to arise from the lower part of the 
inner edge of the septa, their size diminishing as 
they approach the columella. 
Plates nearly equal, very slightly salient, and 
closely set ; their lateral surfaces strongly granulated, 
and sometimes presenting traces of imperfect dis- 
sepiments. They form four or five cycles, and the 
systems are equally developed. 
Pihs nearly equal, straight, closely set, projecting 
very little, and delicately granulated. 
ANALYSIS OF BRITISH SPECIES. 
Plates forming five imperfect cycles: cup elliptical . . . I'axilianus. 
Plates forming four imperfect cycles : cup circular . . . 
Ribs obsolete below I'hulenm. 
Ribs very salient below pteropus. 
