234 MADREPORARIA. 
encrusting surface at one time in contact with stones or pebbles, while between these, small 
pebbles are seen embedded in the coral. The high, sharp walls make the calicles very 
conspicuous ; they occur over the whole stock even down to the edge of the base; the surface 
is only smooth in the bases of deep valleys or clefts. 
a, (Pl. XXXIII. fig. 6a.) Zool. Dept. 92. 1. 13. 9. 
Forms with ridges broken up.—Two other forms with similar calicles but rising upon a 
different kind of base (dead previous growths) have the ridges more or less broken up into 
rather crowded clusters of rounded flat-topped and flattened knobs, though sometimes still 
running for 5 to 6 em.as ridges. The presence of sediment in the valleys between the knobs 
suggests that this may have caused the breaking up of the corallum into so many separate 
flattened irregular stems. The walls flatten down quite early in this specimen because the 
sides all dip down into narrow clefts between the separate knobs and ridges. Where the 
walls are lower there is a tendency for the pali to become more conspicuous, 
bd. Zool. Dept. 92. 1. 13. 19. 
C. Zool. Dept. 92. 1. 13. 17. 
d. Part of ¢, in spirit. Zool. Dept. 92. 1. 18. 24. 
é. Zool. Dept. 92. 1.13. 4. 
é, and eo, Parts of e, in spirit. Zool. Dept. 92. 1. 13. 27. 
Columnar forms.—In addition to the above are two large specimens from Muscat, 
consisting of clusters of knobbed and gradually swelling columns, smooth, round and narrow 
at the base, where they rise either from the thick encrusting layer, or from the tips of similar 
columns of a previous growth. These columns fuse and branch, but are full of interstices 
which run through the heart of the stock. The walls are either sharp and conspicuous over 
the whole stock down to the edge (ef. specimen f and one small patch of g), or else flatten out 
just below the tips of the columns (cf. the greater part of g). 
f. (Pl. XXXIV. fig. 6.) Zool. Dept. 1900. 7. 9. 2 
g- Zool. Dept. 1900. 7. 9. 1. 
Stunted forms.—There are three of these: they consist of dense clusters of short, stunted, 
fusing and branching columns, little more than stalked knobs, the tops of which are slightly 
flattened, and tend all round their edges to run out into smaller knobs. The stocks are full of 
interstices. The calicles have the typical sharp walls, but instead of the intra-calicular skeleton 
being deep down and ragged, it is high and flat, and with the ring of pali forming a central boss. 
The question as to whether this ring of pali is a sufficiently marked character to justify 
the specimens being described under another heading, is apparently answered in the negative 
by the fact that here and there traces more or less marked of such rings occur on specimens 
b toe. The calicles down the sides are quite flush with the surface. 
h, Zool, Dept. 92. 1. 13. 18. 
j. In spirit. Zool. Dept. 92. 1. 13. 29. 
The third is a small free stock which appears to have rested on the mud. It was collected 
at Muscat, at 6 fathoms, by Mr. R. Kirkpatrick. The calicles are slightly more typical in 
having the ring of pali less prominent than in / and j. 
k. Zool. Dept. 1901, 3. 26: 1. 
