1921 PROPLANULITIDJE 33 



Mar. 



last few septa before body-ch. may show much degeneration, and should, 

 where possible, be avoided. 



Genera, Proplanulites, Teisseyre, Wagnericeras, nov., see below, 

 Crassipktnulites, nov., see p. 41 ; Obtusicostites, nov., see p. 42 ; Kin- 

 keliniceras, nov., see p. 42 ; Pictonia, Bayle, Rasenia, Ringsteadia, 

 Salfeld. 



• . -.Of these genera Obtusicostites is nearest to the main stem and so to 

 the Pachyceratidau, while Proplanulites is farthest removed, being the 

 most degenerate in all characters. 



Am. albineus, Oppel, Per. mutatis, Waagen and the series placed 

 by Siemiradzki as " Mutationsreihe des Per. Congener Waag." possibly 

 come into this family. 



Wagnerickras, g.n. Genotype, Am. wagneri, Oppel {Am. 

 planula, d'Orb., cxliv). Serpenticone, convergent whorls ; ribs flexed, 

 strong over venter; s.l. somewhat simple, Li at 55mm. est., 40 per 

 cent. + ; Vesulian, or Bathian ; France. 



" Ammon. arbustigerus bildet zusammen mit Ammon. planula d'Orb. 

 (Ammon. Wagneri Oppel non Neumayr) eine besondere Gruppe [von 

 Procerites] welche den Proplanuliten nahesteht " (Siemiradzki, p. 315). 

 But Am. arbustigerus is possibly a Zigzagiceratid, though s.l. is 

 insufficiently developed. 



Proplanulites, Teisseyre 1887, (Amm. Baliner Ool. ; Verhandl. 

 K. K. Geol. Reichs., p. 48) " Proplanulites Konighi Sow. sp. Czerna " ; 



(P- 54)- ; '. 



" Proplanulites Koenighi Sow. sp. Das betreffende Exemplar dieser 



aus den Baliner Oolithen wohlbekannten Art hat einen zweispitzigen 



Antisiphonallobus. Doch ist dieses Merkmal schon innerhalb dieser 



Art unbestandig. . . Proplanulites nv. gen., welches ausser der gen- 



nanten Art noch einige andere als neu zu beschreibende Formen umfast, 



wird von mir an entsprechender Stelle naher charakterisirt werden." 



The genus is founded on " Propl. Koenighi " (sic) from the Balin 

 Oolite — this specimen of Teisseyre's from Czerna thus becomes the geno- 

 holotype : it is figured (with its suture-line ?) by Teisseyre (Proplan. ; 

 Pamiet. mat. Akad. Krak. XIV, 1887, iv, 1, v, 1). The two-pointed 

 antisiphonal lobe is, perhaps, as he says, " unbestandig," inconstant — 

 possibly an abnormality. 



S.l. with EL about equal to, but often rather less than Li ; ES and 

 Si equal in depth ; L2 and aux. 11. rather degenerate. S.l. degenerates 

 much in some series, Li passing from c. 40 per cent, of breadth of whorl 

 to c. 20 per cent, and less. Periphery has two forms : (1) subgibbous, 

 sides subparallel, venter full ; (2) subcuneate, sides converging to a 

 narrow venter : it carries two modes of ornament : (1) ribs cross venter, 

 though with some weakening — (a) they cross straight, (b) secondary 

 ribs being inclined, they cross with a feeble curve ; (2) ribs fail on middle 

 of venter, making a smooth band — a very late attempt to produce the 

 Parkinsonian venter (p. 29) — in some degenerate forms, on cast, a fairly 

 distinct interruption, illustrated by Phillips (Am. koenigi, Geol. Yorks. 

 1829, vi, 24), but exaggerated for his reduced fig. Then, in old age, 

 forms which are subgibbous tend to acquire a subcuneate venter and 

 those that are subcuneate, a subgibbous venter. The rib following any 

 of the obscure Perisphinctean constrictions passes strong over venter 

 in most series. In phaulomorphs, before end of body-ch., a few ribs 

 show strong on venter, finishing off with a sort of collar and short 

 rostrum. 



Callovian, England, Kellaways Clay, koenigi t], Dorset, Wiltshire ; 



