REPORT ON THE REEF-CORALS. 127 
Columella tuberculate, distinct. Synapticulee rarely conspicuous, fused throughout so 
as to give a close and dense texture to the corallum. 
This species may be easily distinguished from Domoseris poresa by the rather finer 
striations of the under surface, by the more isolated projections of the upper surface, by 
the non-perforated septa, by the thinner, nearly entire, less swollen and less irregularly 
discontinuous septo-coste, by its rather conspicuous columella, and by the fused state of 
the synapticule. It has many points of general resemblance to Leptoseris (Mycedium) 
elegans (Milne-Edwards and Haime), but differs from it in essential structure. 
A single large specimen is in the collection. 
Tahiti. 
Locality. 
3. Domoseris regularis, n. sp. (Pl. V. figs. 6-65). 
Corallum broad, explanate, irregularly bent, thin, from about 4 to 5 mm. thick at a 
distance of about 8 cm. from the margin, and very thin at the extreme marginal parts ; 
with supplementary basal attachments. Under surface with well-pronounced depressions 
and prominences marked by fine costal striations. The calicles irregularly scattered, not 
crowded, and rarely or not at all grouped into nodular masses, the projections being low and 
rather small; the fossa small, about 1 mm. wide, rather.deep. The septa of two or three 
cycles, unequal, close, very granulated, perforated ; the septo-costz nearly evenly raised, 
alternately very much thickened, with a rounded upper margin divided into rather unequal, 
broad, blunt teeth; often discontinuous, and, more especially below the more central calicles, 
very irregularly bent, sinuous and contorted. Columella small, inconspicuous. Synapti- 
cule small, irregularly developed, not abundant, nor fused throughout to form a con- 
tinuous, solid lamina except quite at the base. 
This species is easily distinguished from the Domoseris solida by its distinctly toothed 
and more unequal, perforated septa, by its non-fused synapticulee, and by the less elevated 
and more distant projections of the upper surface. From the Domoseris porosa it is dis- 
tinguished by the very thin corallum, by its much less wneven and scarcely rough 
surface, due to the more evenly raised and more equally thickened septo-costee, which are 
much less discontinuous and contorted, by the much less perforated nature of the septa, 
and by the comparatively shght and irregular development of synapticulz. 
Only a fragment of a large specimen, and a very small specimen, were obtained. 
The small specimen is from about 2 to 3 em. wide, irregularly shallow-vasiform, attached 
to and incrusting a portion of a shell. It contains about four distinct calicles which have 
the lower border scarcely at all raised, with the septo-costee irregularly toothed and sub. 
entire. Its growth has been much interrupted by foreign matter, so that the parent 
calicle does not occupy a central position. 
Tahiti, 30 to 70 fathoms. 
Locality. 
