part 4] evolution" of the lipakoceratid.u. 295 



Plate XXV. 



Fig. 1. Oistoceras allceotypum, sp. nov. X '52. From the lower beds of the 

 margaritatus zone, Bracebridge Pit, Lincoln. 

 2. Oistoceras omissum Simpson. Development. From the Oistoceras 

 sub-zone, Wadding-ton, near Lincoln, c, d = Inner whorls X 32 ; 

 e,f= Inner whorls X 37 ; g, 7t = Protoconch X 47. 



Discussion. 



The President (Mr. Gr. W. Lamplugii) congratulated the 

 Author on his lucid exposition of an intricate subject, and com- 

 mented on the high importance, botli to biologists and to strati- 

 graphers, of intensive palaeontological studies of this kind. He 

 wished, at the same time, to call attention to the difficulties felt 

 by the field-geologist, when robbed of his crude nomenclature of 

 the commoner fossils by the precise definition and complicated 

 analysis now attempted by the palaeontologists. For general 

 service some kind of name was essential, but was becoming 

 increasingly difficult to acquire or retain. For example, it 

 was' most desirable to be able to express, as proof that certain 

 beds were Upper Lias, that they yielded Ammonites communis, 

 bifrons, and serpent inns, for every geologist would understand 

 the statement. It might be based, quite soundly, on material so 

 poor that no palaeontologist could name the specimens, or so good 

 that only a very small number of specialists in these particular 

 forms would dare to do so. The growing difficult}^ would have to 

 be met by some means, even if it entailed a duplication of nomen- 

 clature. We might have to continue to use indispensable names 

 in a general sense, perhaps with some indication by type or s}'mbol 

 to warn the specialist. 



The Seceetaey read the following communication from Mr. 



S. S. BUCKMAN: 



The title of this paper is a tribute to Alpheus Hyatt. It is just over 

 50 years ago that Hyatt published his remarkable scheme of Ammonite 

 families and genera — a scheme so advanced for its time and so revolutionary 

 that it found no acceptance in Europe for many long years. Here the later 

 but far more modest scheme of Waagen held the field, j r et even that was very 

 strongly condemned as an undesirable innovation. I can remember in the 

 'seventies' the discussions of leading geologists and my father when they met 

 at his table after their field excursions — the prophecies of disaster to palae- 

 ontology, which would become quite distasteful to students from the multitude 

 of new names. And now w r e see how these predictions have been falsified. A 

 young student in almost his first paper takes one of Hyatt's original families, 

 actually only a small portion of Waagen's genus JEgoceras, and finds it now 

 divided into five genera, which he accepts. But in his critical analysis he 

 discovers that these genera are insufficient : he promptly increases them by 

 80 per cent., admitting at the same time that many foreign species of the 

 family must remain outside of them, so that the number of genera in tliis 

 one family is not quite complete. Further, he shows his grasp of the subject 

 by clearly stating the distinctions of the genera in a few words. 



The family Liparoceratida? is very interesting. In its geological distribu- 

 tion it illustrates the principle of faunal repetition alluded to in my last paper 

 communicated to the Society. In its morphology, showing successive waves of 



Q. J. G. S. No. 296. 2 a 



