184 MADREPORARIA. 
the longest about 8 mm. and provided with 3 or 4 verruciform buds. A few hemicotyloid or 
subimmersed corallites are scattered between the others. The upper surface of the main 
divisions is provided with numerous hemicotyloid or appressed tubular corallites arranged 
irregularly, about 2 mm. diameter, with a wide aperture and star of six narrow septa. The 
branchlets on the upper surface are erect or suberect, 2 cm. long, and rarely over 4 mm. 
diameter at the base if simple, but others which are divaricately branched may be 6 mm. 
thick. Each branchlet consists typically of an elongate and somewhat club-shaped axial 
corallite bearing buds which are hemicotyloid and irregular near the base, but become 
tubular above, where from one to four more or less radiating corallites have about the same 
diameter, and attain to the same height as the axial corallite. Axial corallites 7 to 12 mm. 
long, greatest diameter 4. to 4-5 mm., margin much rounded, aperture under 1 mm, diameter ; 
in many cases bud-corallites occur within 2 to3 mm. of the apex; septa moderately developed. 
Corallum dense ; surface finely and closely echinulate, in some parts showing linear series 
of pits beneath the surface film. 
Habitat not recorded. 
O=6: -—— Sir E. Belcher [P.]. 51. 11. 14. 28. 
9. Subgenus TRACHYLOPORA. 
Axial corallites slender, elongate and cylindrical; margin plane or suddenly contracted, 
not rounded; wall thin, but usually dense. A second cycle of septa is usually wanting even 
in axial corallites. Distal parts of the elongate corallites without buds; the latter rarely reach 
to within 5 mm. of the apex. The form of the corallum in the species known is either of the 
bottle-brush type, with very numerous radiating twigs, or flabellate and subhorizontal with 
the elongate corallites and twigs chiefly on the upper surface. 
This subgenus is closely related to Rhabdocyathus, which has typically a stouter axial 
corallite with a rounded margin, around which bud-corallites often extend to within 2 mm. 
of the apex. In Rhabdocyathus the axial corallites are also provided with 12 septa. In some 
respects M. rambleri is intermediate between the two subgenera ; but although in this species 
bud-corallites occur nearer to the apex of the axial corallites than is usual, the axial 
corallites themselves agree in form and diameter with Trachylopora, to which it is 
therefore referred. 
A. Corallum of the bottle-brush type. 
a. Aperture of the axial corallites not suddenly contracted. 
198. Madrepora echidnza. 
? Oculina echidnea, Lamarck, Hist. Anim. sans Vert. t. ii. p. 286, ed. 2, p. 457; Deslongchamps, 
Encycl. p. 575 ; ? M.-Edwards & Haime, Coralliaires, t. iii. p. 151 (non Dana, non Ortmann). 
Heteropora echidna, Ehrenberg, Corallenth. d. roth. Meeres, p. 111. 
