IN THE COCOS-KEELrxa rSLANDS. 



45 



stated Av, rif) the mode of pemmation is centrifiip^al in Isoiwra, ft« in 

 ^laiireporn, str. Other points distinguishing Aiia^ropora from moat 

 spei'ies of Madr<?p<vrjTi aro tiiti forraation of the axiK of the branches l»y a 

 sprmfry cnenonchyiua, whcrea^s in many (if not all) Madrepone tliis, in 

 a^conlance with fcho centrifnpil habit of budding, is occupied to a greater 

 or lcsj4 distance from the ends of the branches by the downward prolon- 

 gations of the sepfa and tlie intersep^ftl spaces of the apical calicle. The 

 rudimentary condition of the externa! part of the calicle dietingnishea 

 Anftcroj)om ; for although it is commonly found (I refer to the sunk 

 calicles oc<?urring in so many species l*tween the prolonged iubnlar or 

 nariforni ones) in stomr, it is never, bo far tis my knowledge extends, found 

 in fifl the cahVles in any Madrepora. 



Although in its general appearance it differs remarkably from even 

 the hrancheil species of Montipora. yet the structural differences which 

 separate Anacropora from this genns are 'very far les6 distinctive tlian 

 those which separate it from MiwlreporA, In the first place, in spite of 

 its external resemblance to Madrepora, it has the same system of calicular 

 budding (viz. centripetal, from the distal crenenchyma) which we find 

 well developed in theramoi*e Montipora; the tralvecnlarstmctiireand tlio 

 two-cycled arrangement of the septa is the same in both genera. On the 

 other hand, whei-eas in Anacrofkira there is always an undifferentiated 

 coenenchymal af>ex, devoid of caliclc<», to the branches, in Ifontipora thia 

 ftfiex appears always to l»ear at least one calicle on its surface. In Anacro- 

 pom the ea tides are always rather distant and fend to form lines, and are 

 slightly raisetl alx)ve the surface, fonning low hill-Hke eminences, whereas 

 in the mmose Moiitiiiora (e-.tt. digitata, Datm, divaricata and su|>erficiali«, 

 Briitj^emohii), which on the whoh* most clo=iely approach Anacropora, the 

 calicles open flush with the surface, are crowded indiscriminately. and no 

 linear arrangemeut is apparent. In Montipora foliasa, it is true, the 

 ealiele«=«, esf>ccially on the posterior ai?pect of the eoralkim, are elevate*! in 

 a similar manner; but the foliate growth and the monticnlar inter-cnXi- 

 rular eminences of the upper surface seem to remove this species far from 

 the ranjoso Sroiitfporje. Jt seems to nie not improlmble that, for tho 

 reasons I have indicated, these ramose forms may have to be separated 

 from the foliate and massive s^jccies of Montipora. 



'i'he relations of Anacropora may t* thns sliortly stated Anacropora 

 has tho general growth of IMailrei>ora, but the manner of budding of 

 Montipora. 



Tho following ia ft description of the single species referable to this 

 genus which I am able to describe; owing to the interest attaching to the 

 type, I have allowetl myself to give its characters at full length :— 



Corallum branching frequently, dichotomously, occarionally snhtri- 

 chotomously ; branches given off in snccession in a euhspiral manner, 

 the planes of snecessive bifurcations varying from ahont 30"^ to 100'^ with 

 regard to each other ; angle l»etween branches conq>osing tuTureation 8fl^ 

 to IW. Stem and branches slightly curved, the apical branches more 

 strongly fo, cylindrical, except tho terminal branches, which tend to curve 

 outwards and tawr gra<lually to |K>ints ; diameter, main axes 6-7 millim., 



lietween bifurcations of nmin branches about 30 millim,, temunal twigs 

 25 millim. long. C'alicles arranged more or lees definitely, for tho most 

 ]jart in series which follow approximately the longitudinal axis of the 

 stem and hninchr-^. tfic cali^'b^^ of one series alternating with those of the 



A-VAcnopOBA roRBKSi, MidJty. 



