DESCRIPTION OF CORALS. 153 
proximal position they accorded perfectly with those which belong to well-known 
Cellepore. The opening of the vesicle was easily detected by looking obliquely 
into the mouth of the cell. 
Family TuBuiporina. 
Idmonea coronopus? (De France). (Tab. IX. fig. 24.) 
Bifurcated ; branches diverged excentrically, more or less rounded on the 
back ; transverse rows of tubular openings blended along the medial line, forming 
a crest ; crest less in height than the depth of reverse portion of the branch. 
De France, Dict. des Sc. Nat. t. xxii. p. 565. De Blainville, Man. d’Actinol. 
p. 420 (1830-34). Milne-Edwards, ed. 2. Lamk. Anim. sans Vert. t. ii. p- 281; 
Notes (1836); also, Recherches sur les Polypes, Mém. sur les Crisies, &c. p. 23- 
pl. 12. £ 3 (1838) ; or Annales des Sc. Nat. 2nd Series, Zoologie, t. ix. ple i2: 
f. 3. Michelin, Icon. Zooph. p. 172. pl. 46. f. 16 (1845 2). 
The characters of this coral were so imperfectly ascertained, even with respect 
to the specimen examined, that the above notice and following remarks must be 
considered as indicative of only a small portion of the actual structures. In the 
attempt to identify it with published tertiary species of equivalent geological posi- 
tion, great difficulty was also experienced in the endeavour to ascertain the exact 
or full characters of either Idm. coronopus or Idm. gradata, the two Paris basin 
species originally described by M. De France (opus cit.). With regard to the 
first, the statement, ‘“‘ cellules rhomboidales et disposées en rangées opposées sur 
une des surfaces du Polypier, ou la réunion de ces rangées forme une sorte de 
créte,” might be readily assumed as expressing the structure of the Bracklesham 
coral; but M. De France did not accompany his description with figures, nor 
were any afterwards added by M. de Blainville in his ‘ Manuel d’Actinologie.’ 
Dr. Milne- Edwards, it is believed, was the first author by whom the species was 
illustrated ; but his delineations of it cannot easily be made to accord with the 
original notice just quoted. By reference to the ‘Annales des Sciences Natu- 
relles,’ or ‘Recherches sur les Polypes,’ it will be found that the transverse rows 
of tubuli instead of uniting and forming ‘‘ une sorte de créte,” are widely sepa- 
rated along the mediai line: nor is M. Edwards successful in reconciling the dif- 
ference. The branches are farther shown to be triangular, and the rows of tu- 
buli to extend backwards nearly to the dorsal surface. These representations 
agree perfectly with his description ; but a simple comparison of either with the 
