THE FORAMINIFERA OF THE KERIMBA ARCHIPELAGO. 297 



of the organism, whether free or attached, and in the absence of 

 information on this point and the impossibility at the present 

 time of communicating with Dr. Rhumbler or of examining his 

 specimens, the question of the identity of the two forms must 

 remain temporarily unsolved. If it turns out that Vanhoeffenella 

 gauss ii is identical with the abnormal form of Iridia represented 

 by our figure 10, it will become a question for experts in the 

 rules of nomenclature whether or not his name should have pre- 

 cedence, but we do not feel inclined to accept his views on the 

 window theory to account for the existence of the membrane. 

 The glare of tropical sunlight in the shallow waters of the 

 Kerimba reefs would certainly not be an advantage to the 

 organism, and we prefer the theory we have expressed, that these 

 are abnormal forms which have grown between two large sand- 

 grains and have subsequently become detached. Of course any 

 astrorhizid growing under such conditions would have a tendency 

 to form a structure similar to Vanhoeffenella, and unless 

 Dr. Rhumbler found other specimens attached or free similar 

 to the adult Iridiee which we have figured, the identity of the 

 two organisms remains unproved and our genus Iridia holds 

 good. 



The Kerimba material has supplied us with a very fine series 

 of those double shells of Diseorbina which one of the authors 

 has recently exhibited in support of his conviction that the so- 

 called phenomenon of plastogamy is in truth a process of budding. 

 We have prepared a series of such pairs from the earliest 

 primordial emerged chamber to the young but adult and almost 

 independent shell. 



The other important observations arising out of the material 

 are afforded by the study we have been able to make of the vast 

 quantities present of the various species of the genus Cymbalo- 

 pora. We have been able to make a series of sections and 

 dissections showing most clearly and in all its stages of develop- 

 ment the peculiar dual nature of the large terminal balloon- 

 chamber of Cymbalopora bidloides d'Orbigny. It was Earland 

 who first (in 1902), called attention to this feature*, which had 

 curiously enough escaped in turn the observation of d'Orbigny, 

 Brady, Mobius, and Sir John Murray, all of whom paid special 

 attention to the species. The detailed results of our observations 

 are in course of being published f and are too elaborate and far 

 reaching to go into at length on this occasion. We have found 

 many specimens the float-chamber of which has been found on 

 dissection to be filled with desiccated remains of Xanthellse such 

 as were noted by Sir John Murray in his ' Challenger ' Note 

 Books. And we have separated as a new species, a smaller and 

 more compact form of Cymbalopora, in which the inner float and 

 outer balloon chambers are so closely connected as to be practically 



* A. Earland on "Cymbalopora bidloides d'Orbigny and its Internal Structure," 

 Journ. Qnet. Mi'cr. Club, ser. 2, vol. viii. 1902, p. 309. 



f Heron-Allen, in Phil. Trans. Roy. Soc. London, 1915. (In the press.) 



