QUEENSLAND AND TIIE NEW HEBKIDES. 32l 



JJimemions. — Height 5-24 mm., average 8-10 mm. ; diameter^ capitnliim 

 3-4 mm., column l'5-2 mm. 



Locality. — Collected at Masthead Island, Queensland, by Mr. C. Iledley's 

 expedition in 1904. 



The specific name pigmentatus refers to the circular zone of pigment- 

 granules iu the mesoffloea of the column-wall. 



Column-ioall. — Beneath the cuticle of many of the shorter polyps one or 

 two little grains of coral are to be seen. In many of the longer ones this 

 process has gone mnch further, and the basal half of the polyp is covered 

 with little projections each containing a number of coral fragments. 

 Sections show that a very irregular form of incrustation has taken place. 

 The coral fragments are not distributed regularly round the column-wall, 

 they remain closely packed together and occupy the whole width of the 

 mesogioea immediately interior to their point of entry. In many cases single 

 l^ieces break through the eudoderm and enter the coelenteron. These coral 

 fragments are sometimes sufficiently numerous to make the polyp quite 

 rigid, and occurring as they do in the slender basal part of the elongated 

 polyps must afford a great support. Seven polyps of different heights were 

 sectionized, and in each case small fragments of coral were found lying free 

 in the coelenteron. 



The column-wall is comparatively thin, averaging '15 mm. The proximal 

 paii is thicker than the distal. A yellow cuticle and a very thick subcuticle 

 are present. In longitudinal sections the column-wall frequently presents a 

 correspondingly convoluted appearance to that of Z. Sliackletoni (Haddon & 

 Duerden, 7). But in this species the ectoderm and mesogioea proper take 

 part in the folding. Fig. 12 is a drawing of a much less wrinkled specimen. 

 The ectoderm is discontinuous, but the connecting strands of mesogioea are 

 neither so numerous nor so regular as in Z. sandvicensis (fig. 12). A large 

 number of nucleated ectodermal cells are present in irregular groups, and 

 the ectodermal spaces contain also many large oval nematocysts. The meso- 

 gioea is thinner in the distal part of the column and capitulum than in the 

 proximal part. 



An irregular row of globular lacun?e lies in the mesogioea immediately 

 below the ectoderm (PI. 45. figs. 12, 13), extending throughout the length 

 of the column and into the proximal portion of the capitulum. Generally 

 these globular lacunai appear quite empty, but they may contain a little 

 pigment and more rarely a single nucleated cell. Duerden has described the 

 same structures, but wdthout contents, as occurring in Z. Solanderi (8). 



In close proximity to these spherical cavities and scattered partly among 

 them is a very distinct circular zone of pigment-granules. Its presence gives 

 a characteristic appearance to transverse sections of this species (PI. 45. 

 figs. 12, 15). This zone is present throughout the length of the colunni, and 



