Madreporarian Snhfav\ih/ Montiporina*. 119 



In 1884 Ridley * denied the close relationship between 

 Jilotitipora and ^f(ldrepor<l claimed by Dana. The forms of 

 the latter which, owiii^ to the obscuration of the apical polyp, 

 Dana thought might constitute a connecting-link between the 

 two, lent, according to Ridley, no supj)ort to such a con- 

 clusion, inasmuch as the apical polyps in these types are not 

 really absent, but only inconspicuous owing to their multi- 

 plication. Further, it was claimed that a far-reaching 

 ditlerencc in the method of budding separated the two. In 

 Madrepora the budding is said to be centrifugal, the fresh 

 buds forming below the central apical polyp, while in Monti- 

 pora undifferentiated coenenchyma takes the lead and the 

 fresh polyps api)ear abov^e one another. I shall endeavour 

 to estimate later on to what extent this is a true diagnosis 

 of the morj)hological difference between Madrepora and 

 Montijjora. 



J)nncan, in 1884 f, in his revision of the Milne-Edwards 

 and llaime system, tbllowcd these authors in placing Monti- 

 pora with Porites. 



Quelch, in 1886, in his description of the * Challenger ' 

 Reef Corals, placed Montipora among Madreporida3, as does 

 Miss Ogilvie in her recent " Microscopic and Systematic 

 Study of Madreporarian Types of Corals " %. 



Lastly, in 1889 Dr. Ortmann §, after following Dana in 

 1888, classed the Montiporidai with the Madreporidce, Pori- 

 tidaj, Turbinariidfe^ &c, as independent families of the Madre- 

 poracea. 



The conclusion here arrived at on this point, viz. that the 

 Montipora belong unmistakably to the Madreporidse, is based 

 upon a study and comparison of nearly 400 specimens, 

 divisible into some 120 types, of which more than half are 

 new. 



The youngest colony that I found is contained in a small 

 oval epithecal saucer, 3*5 millim. long diameter (PL 11. 

 figs. 1, 2). This saucer is filled with a spongy cosnenchyma. 

 One polyp, about '25 millim. in diameter, opens in the 

 highest part of the coenenchyma and near the centre, while 

 a few smaller ones open between it and the epitheca. It 

 seems to me that there is no escape from the conclusion that 

 this largest and most central polyp is the parent polyp of the 

 colony, and that the coenenchyma stretching from it to the 

 epitheca in which the other polyps open is, or more correctly 

 was, before the other polyps appeared, its thick porous wall. 



* Ann. & Mag. Nat. Hist, (o) xiii. p. 284. 

 t Journ. Linn. Soc, vol. xviii. 

 X Phil. Trans, vol. clxxxvii. (1896). 

 § Zool. Jahrb. vols. iii. and iv. (syst.). 



9* 



