448 ME. S. S. BTTCKMAN ON [Aug. 1906, 



where the perforate stages are so extraordinarily represented, 

 there should be no example of the stage connecting perforate 

 and imperforate. It is sufficiently remarkable, in any case, that 

 there is only this one subperforate example. But, whatever the 

 horizon of this specimen, it does show the connexion between 

 perforate and imperforate stages ; it is most important evidence 

 for that. 



Since the above was written I have seen in the British Museum 

 a specimen, B. 10824, 'from the north flank of Tatra, E. I. Murchi- 

 son Collection.' It is a fragment of a diphyoid embedded in 

 matrix. 



Imperforate Stage. 

 Triangulate. 

 Pygope (?) misilmerensis (Gemmellaro). 



Terehratula misilmerensis, Gemmellaro, 1871, pi. i, figs. 6 & 7. 



This is a rather thick form, and has a half-moon front, the 

 same character as is noticeable in P. solidescens. Gemmellaro's 

 claim that the form is distinct from Antinomia pileus (Terehratula 

 triangulus) seems to be quite justifiable. It is from the T. janitor- 

 beds of Sicily. 



Pygope (?) sttbtriangulata (Guembel). 



Terehratula suhtriangulata, Guembel, 1861, p. 563. T. euganeensis, Pictet, 1867, 

 pi. xxxiv, fig. 7 only. 



E em arks. — Guembefs name precedes Pictet's. His description, 

 unaccompanied by a figure, seems to indicate such a form as Pictet 

 has figured as T. euganeensis (pi. xxxiv, fig. 7), a more massive and 

 less triangulate species than his other forms of this name. Guembel 

 says that his species comes from the Middle Neocomian. 



Pygope (?) euganeensis, Pictet. (PI. XLI, fig. 16.) 



Terehratula euganeensis, Pictet, 1867, pi. xxxiv, figs. 5 (take as type) & 6 (5, 6, 

 ' echantillons typiques' Pictet, p. 183). ?T. triangulus; Quenstedt, 1871, 

 pi. xlviii, fig. 11 (not 9, 10). 



Pictet says that this is a Neocomian species. 



Quadrangulate. 

 Pygope (?) eectangulaeis (Pictet) 1867. 



Terehratula rectangularis, Pictet, 1867. 



Note. — Distinct from Antinomia pileus (Brug.) not only by its 

 shape, but because its side-margin is straight, not curved, and sub- 

 acute. Pictet says that this species comes from the Eed Ammonite- 

 Limestone [Portlandian] ; this is against its being a descendant of 

 Terehratula janitor : it is difficult to say to what series it belongs. 



