MADREPORA. oll 
another. Diameter of main branches 2°8 to 3:3 cm., length about 35cm. Penultimate 
divisions nearly 2 cm. diameter, about 4 em. long, and with a crown of buds at the apex. 
Axial corallites nearly 4 mm, diameter and 4 mm. exsert ; sometimes 4°5 mm. diameter, with 
only 1 mm. aperture and a very thick porous wall. Radial corallites large, appressed, half 
tubular, up to 6 mm. long and 3 mm. broad, but a little irregular both in size and disposition. 
There are no truly immersed corallites, except in the lines of fusion. Directive septa long, 
the others shorter, with or without a rudimentary second series. Corallum stony, but a 
little porous ; surface spongy-echinulate ; wall strongly ribbed, becoming echinulate below. 
The above description is based on a specimen in the Paris Museum, from the Galapagos 
Islands. Another specimen, also forming part of the collection of M.-Edwards, but without 
habitat, differs im having smaller radial corallites, 3 mm. long and 2 mm. diameter; the 
apex of this specimen is not preserved, so that one cannot decide if the axial corallites were 
of the same size as in the type. 
Galapagos Islands. 
4. Madrepora intermedia. (PI. I. fig. C.) 
Madrepora intermedia, Brook, Ann, Mag. Nat. Hist. 1891, vol. viii. p. 463. 
Corallum arborescent, similar to that of M. secundain habit. Main branches 2 to 2°5 em. 
thick and 25 em. long, moderately subdivided, especially near the apex. Ultimate divisions 
3 to 6 cm. long and 1 em. or more thick, gradually tapering to a blunt apex, or more rapidly 
tapering and pointed. Axial corallites 2°5 mm. diameter, 0°5 to 2 mm. exsert, but usually short ; 
aperture large, frequently oval; primary septa well developed, second series not prominent. 
Radial corallites tubular, spreading, very variable in length and also in diameter. The 
majority extend almost at right angles to the branch, excepting near the apex, and have a 
more or less oblique aperture; they are about 3 mm. long and 2 mm. diameter ; wall firm, 
but not thickened. Numerous short tubular to subimmersed corallites occur between the 
others, varying from 1 to 15 mm. in diameter. The corallites become short and thickened 
wart-like on the main branches, whilst on the under surface the majority are immersed. 
Primary septa narrow, but the directives are moderately prominent, and in the older parts of 
the corallum may be broad. Corallum very porous, surface reticulate and echinulate ; wall 
striato-echinulate, becoming later echinulate in linear series. One specimen resembles 
M. muricata f. palmata in habit, and consists of a thick solid frond with incipient branches 
on the upper surface and numerous short ones at the periphery. 
This species differs from M. secunda in the form and markedly unequal size of the 
corallites. From M. muricata f. cervicornis it differs in the form and angle of the corallites, | 
the density of the corallum, and also in the presence of numerous immersed corallites, 
particularly on the under surface of the larger branches. 
Indian Ocean: Maldive Islands. 
a,b. Maldive Islands. Purchased. 86.11. 22.6 &10. (Types.) 
c. Maldive Islands. Purchased. 86. 11. 22.11. (Var.) 
F 2 
