572 mr. l. f. spate: on [Dec. 1913, 



Perisphinctes (Ataxioceras) ^;nea8 Gemmellaro. 



1877. G, G. Gemmellaro, ' Faune Giur. & Liass. della Sicilia ' p. 162 & pi. xx, 

 fig. 12. 



1898-99. J. von Siemivadzki, 'Monogr. Beschreib. d. Ammonitengattung Peri- 

 sphinctes ' Palseontographica, vol. xlv, pp. 184 & 342. 



1898. A. de Riaz, ' Descr. des Amm. des Couches a Peltoceras transversarium 

 de Trept (Isere) ": as P. virgulatus (Quenst.) p. 20 & pi. x, fig. 4.; 



I possess only half an ammonite, measuring about 70 millimetres 

 in diameter ; but the fine costation and somewhat flat compressed 

 section make this common fossil of the transversarius zone easily 

 recognizable. 



Siemiradzki unites De Eiaz's ammonite with Gemmellaro's type ; 

 but in the latter the costation is certainly much finer and the 

 umbilicus larger — characters in which my specimen comes very 

 near to the type. 



Perisphinctes (Ataxioceras) cf. MiCHALSKii Bukowski. 



1898. J. von Siemiradzki, 'Monogr. Beschreib. der Ammonitengattung Peri- 

 sphinctes ' Palseontographica, vol. xlv, p. 188 & pi. xx, fig. 1. 



1898. A. de Riaz (' P. schilli ') ' Descr. des Amm. des Couches a Peltoceras 

 transversarium de Trept (Isere) ' p. 33 & pi. xii, fig. 6. 



The figures cited above only represent outer whorls, whereas 

 my specimen consists of half a young ammonite measuring not 

 more than 28 mm. in diameter. The section with its greatest thick- 

 ness near the umbilical border, the amount of evolution, and the 

 character of the prominent costation (showing a very strong hook 

 at the umbilical end of the ribs), seem, however, to agree excellently 

 with this form. 



The ammonite occurs in the transversarius zone of Niort and 

 Trept, as also in the cordatus beds of Czenstochau. 



Perisphinctes (Ataxioceras) cf. depereti De Eiaz. 



1898. A. de Riaz, ' Descr. des Amm. des Couches a Peltoceras transversarium 



de Trept (Isere) ' p. 19 & pi. x, fig. 1. 



1899. J. von Siemiradzki, ' Monogr. Beschreib. der Ammonitengattung Peri- 



sphinctes ' Palaeontographica, vol. xlv, p. 343. 



The small and badly-preserved specimen which I refer to this 

 form agrees very well with De Eiaz's figure, but the flexiradiate 

 character of the ornament is not very pronounced. It is, therefore, 

 possible that the ammonite does not even belong to the subgenus 

 Ataxioceras, and may in reality form the inner whorls of a true 

 Perisphinctes, such as that figured by De Eiaz on pi. vii, fig. 4 of 

 the above-cited work (as P. lucingensis Favre), which is considered 

 by Siemiradzki to be P. jelslcii Siem. There is little resemblance to 

 the typical development of the latter form, however, though a true 

 P. lucingensis Favre from Chavaz (Savoy) in my collection is con- 

 siderably nearer. However, since the fact that the peripheral part 

 of my specimen is worn may account for the indistinctness of the 

 flexiradiation, and since in other respects the specimen closely 

 resembles De Eiaz's form, I prefer to unite it with that form 

 rather than with the other ' species ' mentioned. 



