MADEEPOEA. 103 



The specimens referred by Ehrenberg to H. microclados appear referable to two, possibly 

 to three species. Those which he mentions as forming part of the Berlin-Museum collection 

 are, with one exception, identical with M. spicifera, Dana. As already indicated by Studer, 

 slight differences occur ; but nothing which, in my opinion, entitles them to rank as a distinct 

 species. Ehrenberg, however, also refers to a fine specimen in the cabinet of the " Gesell- 

 schaft der naturforschenden Freunde." This specimen also is now in the Berlin Museum ; it 

 differs specifically from the other specimens, and is practically identical with the type of 

 M. flabelliformis, Ed. & H. On comparing the various specimens with Ehrenberg's diagnosis, 

 I find that the specimen formerly in the possession of the " Ges. naturf . Freunde " agrees 

 closely — so closely, indeed, that it appears to have been the specimen on which the diagnosis 

 was based ; on the other hand, the remaining specimens do not conform to the description. 

 Under these circumstances it appears necessary to regard the specimen in question as the 

 type, and the others as M. spicifera, Dana. In this case, M. flabelliformis, Ed. & H., becomes 

 a synonym. The following is a description of the specimen : — 



Corallum flabellate or shallow vasiform ; the part preserved consists of a frond 26 cm. 

 high and 24 cm. wide above, but tapering almost to a point at the base. Under surface 

 complanate ; branches laterally compressed, 12 by 8 mm., rather distantly coalescent. Surface 

 almost naked, with numerous immersed corallites 0*75 to 1 mm. diameter, and a few short 

 branchlets pressed into the general plane, 1 to 1'8 cm. long and about 4 mm. thick ; each 

 consists of an elongate and thick axial corallite with subimmersed radial buds. On the upper 

 surface the branchlets are slender, frequently oblique and rather distant, 1 to 2*5 cm. long 

 and 4 or 5 mm. thick at the base. Axial corallites 1'5 to 2 mm. diameter and 1 to 3 mm. 

 exsert, or even more ; wall not much thickened ; a few of the apices are proliferous. The 

 radial corallites of the main divisions are immersed or subimmersed. At the base of the 

 branchlets the corallites have the outer part of the wall short and thin, and the aperture is 

 wide ; towards the apex the wall gradually becomes more elongate and labellate, and spreads 

 at an angle of about 40° ; length 1 to 4 mm., diameter ] '5 mm. ; the wall is always thin, and 

 the aperture wide and circular. Corallum fragile j siirface reticulate and strongly echinulate ; 

 wall broadly striate, echinulate near the base. 



The type of M. flabelliformis, Ed. & H., consists of a fan-shaped frond 32 cm. high and 

 38 cm. across the broadest part. It agrees closely with the specimen already described in the 

 majority of its characters. The branchlets on the upper surface arise singly or in groups of 

 3 to 6. The upper radial corallites are labellate or half-tubular, a little unequal, 1-3 mm. 

 diameter and up to 2'5 mm. long. The surface of the corallum consists of a close vermiculate 

 network with fine eehinulations. All the septa are narrow, and in the immersed corallites are 

 almost indistinguishable. 



Indian Ocean, 



p2 



