440 



ME. S. S. BUCKMAN ON 



[Aug. 1906, 



From Pictet [29] pp. 155, 156, and from other authors, it is possible 

 to gather the distribution of diphyoids into the various strata — 

 Berriasian, Stramberg Beds, and Di^rfiya-Kailk ; but, though useful, 

 this is not sufficiently exact for zoological purposes. For instance, 

 we cannot say which, if any forms, distinguish the Upper from the 

 Lower Dvphya-Kalk ; but the wide and incorrect use of the term 

 Terebratula diphya is perhaps responsible for that. 



Then from Pictet [29 J p. 309, it may be learnt that these diphyoid- 

 yielding strata are divisible into some eight or nine beds, one of 

 which alone is 1500 feet thick. It is obvious, therefore, that such 

 a bed as the Dijjhya-Xdlk, wherein are found species of Antinomia 

 in various stages of development, must have taken a long enough 

 time in deposition to allow of the evolutionary changes required. 



The following Table (II) shows the sequence of the diphyoids, so 

 far as I can interpret the records of various authorities : — 



Table II. — Stratigraphical Sequence op Diphyoids, according to the 

 Information given by Pictet and other Authors. 



Neocomian, 

 Berriasian. 



Pygites diphyoides ; Pygites, bifidate forms : Pygope Duvali ; 

 P. subtriangulata ; P. euganeensis ; Antinomia equi- 

 campestris. 



Stramberg 

 Beds. 



Pygope janitor ; P. deltoidea; P. Puvali (?) ; P. (?) misil- 

 merensis. Pygope, bifidate forms are from Koniakau. 

 [Pictet, p. 155.] 





Antinomia angusta, Upper Diphya-K&Yk. 



Pygope (?) diphya, P. (?) solid esce /is, P. (?) rectangular is, 

 P. rupicola ; Antinomia planulata, A. sima, A. diphora, 

 A. dilatata, A. Catutti, A. cor, A. Quenstedti, A. triqtietra, 

 A. pileus. 



The geographical distribution of the diphyoids is essentially 

 circum-Mediterranean — that is, the southern parts of Europe, and 

 Northern Africa. 



The following are a few references to nomenclature and 

 synonymy — not by any means exhaustive, it is true, but sufficient 

 (it may be hoped) to be a guidance for future work. 1 Por one 

 reason exhaustiveness could not be aimed at, because one of the most 

 important works on this subject has been inaccessible : there is no 

 copy in the British Museum (Natural History), and I have not heard 

 of one anywhere else, of the important work by Zeuschner [38]. 

 Further against exhaustiveness is the fact that many forms of 

 Pygope and Pygites — those in the bifidate stage for instance — 



1 For assistance in this study my thanks are due to my eldest daughter, who 

 traced and pasted on slips for comparison nearly 250 figures of these fossils. 



