﻿PAPILLATE MONTIPOR^. 95 



In addition there are two unbleached fragments from the edges of fronds, the longi- 

 tudinal ridges of which are very tall and thick. The colour of the thin growing edge is bright 

 red-brown, which gradually changes into deep olive-green. This colour, however, tends to 

 whiten along the tips of the ridges, 



h, i. Amboyna. Vienna Museum. 



73. Montipora australiensis. (PI. XVIL fig. 3 ; PI. XXXIII. fig. 8.) 



Description. — Corallum consists of several concentrically arranged, nearly horizontal 

 folia, not standing as separate cones but growing out laterally from some point of attachment, 

 the whole cluster appearing as a semicircular mass. The edges (which are 2 mm. thick) are 

 slightly lobed, the lobes being bulged downward. Each leaf seems to be deeply wrinkled 

 concentrically at intervals, as if the edge periodically drooped and then turned up again ; 

 from the crest of these wrinkles, knobs and small finger-like processes may spring up. 

 Epitheca only developed beneath the dying inner edge of the living zone of each leaf. 



Calicles distinct, star-like, numerous, slightly less than 1 mm. in diameter, six well 

 developed series of septal spines, slightly swollen at their tips, rudimentary secondaries 

 sometimes partly represented. Single calicles often raised 1 to 2 mm. above the surfaces 

 on the papUlas. On the under surface, the calicles are almost as numerous as on the upper 

 surface, regular, and at some distance from the edge slightly prominent, with two cycles of 

 septa ; the primaries thickened and slightly exsert. On smooth portions of the coenenchyma 

 they may be very minute and crowded, as is the case also on the upper surface. 



Coenenchyma shows, in section, a laminated streaming layer, which comes to the surface 

 at the growing edge. For a varying distance from the edge the upper surface is smooth, the 

 streaming layer merely mounting to form the distal walls of yotmg calicles, which are thus 

 nariform (PI. XXXIII. fig. 8). Here and there, round the growing edge, the upper edges of 

 the component laminae are visible as white radiating strise on a pink ground (cf. M. papillosa, 

 M. striata). The thickening layers, upper and lower, are more densely reticular. The lower 

 one gradually becomes almost solid and nearly 3 mm. thick, pierced however by calicles. 

 The upper is of very varying density. Here and there, but not typically, solid trabeculae 

 appear. These rise above the surface either as short single tubercles or else in groups round 

 a calicle, which they lift above the surface (cf M. striata). The reticulum more commonly 

 forms ridge-like papHlse swollen or pointed at the tips, and forming angles and curves 

 which partially surround calicles. The calicle is very often raised by the papilla, into the 

 side of which, however, it is sunk. Where these papillse have formed groups raising the 

 coenenchyma into definite mounds and finger-like processes, the ccEnenchyma between such 

 mounds may be a smooth open reticulum with great numbers of star-like calicles opening 

 on its surface without any protecting ccenenchymatous elevations. 



On the under surface the solid coenenchyma forms a mosaic of plates separated by deep 

 fissures (cf. M, striata). 



