146 MADREPORARIA. 
wide at the base, and about 1 cm. thick. They are smooth, and the tips swell and divide into 
uneven halves. It looks sometimes as if the main stem grew on and threw off smaller branchlets 
first on one side then on the other. The branchlets are short, constricted knobs, with stalks 
about 1 em. thick. 
The calicles are superficial, or slightly pitted, about 1 mm. in diameter. The walls are 
wide and solid looking, being built up of horizontal feathery flakes, on the tops of which are 
thin, straggling granules or threads, which are the beginnings of another layer of flakes. These 
give the surface a velvety appearance. 
The septa are wedge-shaped tongues of thin flakes, with feathery granules along their 
top edges, often continuous with the fine threads on the wall. These show a ring of small 
septal granules, not sharply marked from the wall by any circular furrow, The pali, which 
are small, feathery or frosted, form rather a large open ring, showing the complete formula 
H, fig. 3. A feathery and often flattened tubercle rises in the fossa to near the surface. 
The section shows the horizontal and radial trabecular elements about equally developed. 
This coral was named Synarwa* dilatata by Briiggemann in his MS, Catalogue; he 
gave no description, but labelled the specimen “ Type of Species.” 
A comparison between this coral and P. North Australia 7 (Pl. XXIL. fig. 8, Pl. XXIV. 
fig. 6) shows some resemblance between their calicles and their methods of growth. But, 
though the peculiar manner of forking is seen in both, the stems or processes in this coral are 
very massive as compared with those of No. 7. They may be safely regarded as varieties of 
the same kind of Porites. 
a. Zool. Dept. 46. 7. 30. 24. 
139. Porites North Australia @)2. (P. Australie Borealis seeunda.) 
(BIE XE figs 3); 1 XXIV ties )5:) 
[Port Essington, coll, W. Saville-Kent ; British Museum. ] 
Description.—The corallum rises into round stems which flatten and divide. An old 
stock may consist of a cluster of such stems springing from the surface in an irregular ring 
round a thick flattened stalk (a former stem). All show a tendency to flatten, but some 
have attained a greater width than others, Round bases of stems are from 1°5 to 2 cm, 
thick, and widths of flat tops from 3-7 em. The widest not only fork in, but also at right 
angles to, the plane of greatest width. The depth of the living layer is 10 cm. and more. 
The calicles are all flush with the surface, variable in size up to 1°5 mm, The walls are 
flat, nowhere thick, but rise into slight ridges on the tips of stems and in sheltered valleys. 
They consist of rough frosted granules, the tips of trabecule, mostly arranged in single rows 
between the calicles. The intra-calicular skeleton seen at the surface is also a mosaic of similar 
* On this generic name compare the Introduction, p. 9. 
