66 MADREPORAEIA. 



Description. — Corallum a solid mass, the thick margiu growing downwards, seldom 

 turning outwards as a distinct ridge. 



Calicles, with margins only protruding, or else quite immersed ; apertures irregularly 

 round, diameter 2 • 5 mm. and under. Septa (24 to 30) very unequal, not reaching the half- 

 radius circle, but sloping down from the margin to form a deep, almost cylindrical, or 

 shallower funnel-shaped, fossa. Columella protuberant, irregularly round or oval, rather 

 compactly foliate, not visibly in contact with the septa. Interseptal loculi narrow, in some 

 specimens sharply marked off from the ccenenchyma. 



Coenenchyma, as a rule, finely reticulate but showing great variations. 



There are eight specimens of massive Turbinarians in the Collection, excluding the 

 almost hemispherical masses of T. pcltata. 



I was at first disposed to look upon these as merely massive varieties of other 

 types. Two of the specimens appear to be closely allied to T. elegans, a third to 

 T. irregularis. But on the other hand, the glomerate type of growth appears to be a normal 

 and specifically distinct development. If any classificatory value is to be placed on the 

 diti'erent types of growth, there is no adequate reason for excluding this one which is as 

 marked as any other. 



No two of these specimens are alike, and they could and perhaps should be arranged 

 under eight different headings. I have, however, divided them into two groups under the names 

 stelhdata and glohularis, according as the calicles are generally immersed or protuberant. 

 The protuljerance of calicles in specimens growing rapidly in thickness seems to me to be an 

 imexpected feature worth emphasising. 



I have, therefore, arranged six of the specimens under the old species stdlulata of 

 BlainvUle. The remaining two species come under the next heading, ^. glohularis. 



A section through a large specimen reveals the typical method of gemmation of 

 the Turbinarians. But the polyp-cavities have to lengthen indefinitely to keep pace 

 with the thickening coenenchyma. There are traces of transverse septa (tabula^), as if 

 the animals withdrew from the lower portion of the cavities. Secondary budding of 

 these long polyps is not the rule, althougli it may occur, as in all Tm-binarians. In that 

 case, it is a reversion to a mere primitive and less specialised method than that typical 

 of the genus. 



The largest specimen * is interesting as showing the different growths, one piled on the 

 other ; the upper ones creeping down on all sides over the lower ones. 



The polyps of the Fiji specimens have a yellowish colour. 



a-d. Tongatabu. J. J. Lister, Esq. 



e. Fiji Reefs. H.M.S. ' Challenger.' 



- /. Tizard Bank, China Seas, 5 to 10 fathoms. H.M.S. 'Rambler.' 



* Figured in ' Notes Morphological and Systematic, on the Genus Turbinaria,' Ann. and Wag. 

 Xat. Hist., XV. (1895) pi. xix. 



