288 DR. L. F. SPATH OX [vol. lxxix,. 



be referred to Euphyllites. Whether the Annamese ' Psiloceras ' 

 longipontinum (Oppel) recorded by Counillon l belongs to the 

 same stock is doubtful. Few of the Alpine forms show thickening 

 of the sigmoidal costse at the umbilical end and extreme peri- 

 pheral projection ; but in the genus Euphyllites. which resembles 

 the New Zealand specimens in this respect, the inner whorls are 

 constricted. 



The exanrples now described were first attached to Wcehneroceras 

 [and since recorded as such 2 ] ; but the genus Wcehneroceras was 

 intended to include those forms that like W. circacostatum and 

 W. extracostatum (Waehner) lead up to the typical Schlotheimia, 

 and Wsehner's very careful researches have shown that in these 

 ammonites, before a groove is developed, 3 the ornamentation tends 

 to thicken on the periphery, not at the middle of the side as in 

 early Caloceratids, or at the umbilical end as in the New Zealand 

 forms. Fig. 1 (PL XII), perhaps, most resembles Wcehneroceras in 

 costation, or at least forms included by Hyatt in this genus. But 

 Wcehneroceras megastoma, like JEgoceras panzneri Wsehner, 4 

 rather suggests a tendency in the direction of Pseitdcetomoceras 

 Spath, and ' Wcehneroceras ' emmrichi (Griimbel) and ' W.' guidon i 

 (Sowerby), also included here by Hyatt, lead to the involute 

 Psiloceratids of the Tcammerkerense group, better separated as an 

 independent genus Discampliiceras. gen. nov. 5 The falciform 

 striation and plicate ornament of the body-chamber are so distinct 

 that Hahn 6 was misled into uniting this group with the totally 

 unrelated genus Amphiceras Gemmellaro, of the ibex zone. 

 Moreover, the suture-line, illustrated in fig. 1 c, is phylogenetically 

 ^re-Psiloceras : that is, of Euphyllites type. 



Psiloceras (Euphyllites P) sp. nov. ? indet. (PI. XII, figs. 

 1 «-l c.) 



The remarkably phylloid, if slightly worn, suture-line of this 

 specimen, labelled Wcehneroceras sp. by Mr. Buckman, separates 

 the form from any of the known species of the planorbis to 

 megastoma zones. The fragment, however, some 55 mm. in 

 length, is too incomplete to be named. At the smaller end the 

 cross-section is much less elevated than at the larger, and there 

 may have been crushing of the periphery. The suture-line is of 



1 ' Sur le Gisement Liasique de Hun-Men ' Bull. Soc. Geol. France, ser. 4, 

 vol. viii (1909) p. 528 & pi. xi, fig. 1. 



2 W. N. Benson, ' Palaeozoic & Mesozoic Seas in Australasia ' Trans. N.Z. 

 Inst. vol. liv (1923) p. 42. 



3 See also A. Hyatt, ' Genesis of the Arietidse ' Smithsonian Contrib. to 

 Knowledge, No. 673 (1889) pp. 57-58. 



4 ' Beitrage zur Kenntnis der Tieferen Zonen des Unteren Lias in den 

 Nordostlichen Alpen ' pt. i, Beitr. Pal. (Esterr.-Ung. vol. ii (1882) p. 81 & 

 pi. xv, fig. 1. 



5 Genotype : Mqoceras Tcammerkerense (Guembel) Washner, ibid. pt. ii, 

 vol. iii (1884) p. 113 & pi. xxv, figs. 1-2. 



6 ' Geologie der Kammerker-Sonntagshorn Gruppe ' Jahrb. K.K. GeoL 

 Reichsanst. vol. lx (1910) p. 358 & pi. i, fig. 3 (Amphiceras kammei-lcerense). 



