REPORT ON THE REEF-CORALS. 153 
distinct, of twelve narrow, unequal septa, which meet low down in the cell. Ccenen- 
chyma very dense; surface closely and strongly echinulate throughout, but not striated 
even on the cups. 
A single large specimen of this well-marked species was obtained. Its closest 
ally seems to be Madrepora divaricata, Dana, from which, however, it is easily dis- 
tinguished. 
Locality.—Levuka, Fiji. 
13. Madrepora plantaginea, Lamarck. 
Madrepora plantaginea, Lamarck, Hist. Anim. sans Vert., i. p. 279, 1816. 
. es Milne-Edwards and Haime, Cor,, iii. p. 149. 
A single specimen of this species was obtained. ‘The apical cups are about 3 mm. or 
more in diameter. In the type specimens of Lamarck, one of which has been redescribed 
by Milne-Edwards and Haime, the apical cups of many of the larger branches are very 
abnormally thickened, varying from 5 to 8 mm. in width, and are very short, with a 
broad rosette of small lateral calicles around them, evidently brought about by the 
stoppage of vertical growth and the increase horizontally under unfavourable conditions. 
Madrepora acervata, Dana, referred by Verrill to this species, seems to be distinct 
from it. 
Locality.—Tahiti. 
14. Madrepora cerealis, Dana. 
Madrepora cerealis, Dana, Zoophytes, p. 460, pl. xxxv. fig. 2. 
A fine specimen of this species was obtained. It has grown in an oblique manner, 
forming a spreading cespitose clump, springing from the end of a long, nearly horizontal 
stump. ‘The lateral calicles are often 4 mm. long, the proliferous ones being even more, 
and are tubo-nariform, rostrato-nariform, or even dimidiate ; their exterior is finely and 
closely striated. 
Locality.—Amboina. 
15. Madrepora retusa, Dana. 
Madrepora retusa, Dana, Zoophytes, p. 462. 
A small specimen of this species was obtained. It consists of two erect branches 
bearing a few branchlets above. The immersed calicles interspersed among the prominent 
ones are very small. 
Locality.—Tahiti. 
(ZOOL, CHALL. EXP.—PART XLv1.—1886.) Zz 20 
