﻿32 MR. S. S. BUCKMAN ON BRACHIOPOD [Feb. I908,. 



Plate xii. 



Fig. 1. Beticularia lata (?J Browns^. ' Fig. 10. Brachythyris ohlata (1) ^ow- 

 "'"''' ' erby sp. 



Figs. 11, 12, Br achy thy ris (]) decora, 

 Phillips sp. 

 13, 14. Ambocoelia Urei, Fleming 



sp. • 

 15, 16. Beticularia string ocepha- 

 loides, M'Coy sp. 



2. Brachythyris sp. 



3. Martinia glabra, Martin sp. 

 Figs. 4, 5. Brachytliyru linguifera, 



Phillips sp. 

 6, 7. Brachythyris rhomhoidalis, 



M'Coy sp. 

 Fig. 8. Brachythyriss^. = ^\.^n,^g.% 

 9. Brachythyris sp. = ?pl. xi , fig. 5. 



Discussion. 



Dr. Ivor Thomas congratulated the Author upon a paper which 

 was especially interesting from a philosophic standpoint. The co- 

 operation of the field-geologists would probably be required, in 

 order to substantiate satisfactorily many of the points brought 

 forward. Hall & Clarke divided the Glahrati-^e(it\o\-i of Spirifers 

 into the two groups : (a) Aseptati {=^ Martinia, M'Coy) containing 

 shells in which dental plates and septa are wanting, and (b) Septati 

 in which the shells contain well-developed dental plates or septa. 

 The latter comprised the two groups Martiniopsis, Waagen, from 

 the Pt'oductus-lAmestowe of India, and Mentzelia, Quenstedt. It 

 would be interesting to know the relationship between Martiniopsis 

 and the forms of ' Martinia ' which contained dental j)lates. 



Dr. F. A. Bather remembered the difficulty that he had found 

 in comparing the supposed Martinia glahra of Australia with the 

 European species, and he welcomed the Author's explanation of its 

 origin. This was another illustration of the difference of the 

 Australian Carboniferous fauna from the European, although at 

 first the two were supposed to contain many species in common. 

 It was unfortunate that the Author had not had time to expound 

 more fully those methods of correlating the various stages of 

 phylogeny, ontogeny, and morphogeny, in which he took the lead, 

 at least in this country. In other countries such methods were 

 working a revolution in systematic palaeontology, and in time they 

 would do so here also. 



The Author expressed his thanks for the kindly reception 

 accorded to his paper. In reply to Dr. Thomas, who had men- 

 tioned the genera Mentzelia and Martiniopsis^ he said that there 

 were many glabrous Spiriferids the relationship of which it would 

 be interesting to work out ; and it seemed likely that they would 

 prove to be the expressions of the smooth catagenetic stage of varied 

 ribbed or spinous stocks. 



Postscript to the Discussion. 



[The reference made by Dr. Ivor Thomas in the discussion to 

 Martiniopsis suggests to the A.uthor that a possible reticulate 

 ancestor of such a glabrous form may be looked for in certain small 

 reticulate Spiriferids of the British Carboniferous which have a very 



