7927 TERMINOLOGY 31 



Jan. 



To Am. procerus, Schloenbach (Jur. Amm. Palseont. XIII, 1865, 

 xxx, 1), he gives special attention, and this may now be definitely taken 

 as genolectotype. It has been named (as a syntype) Am. schloenbachi 

 by Grossouvre, 1907 (Six. Congres Assoc. Franc-Comtoise, p. 8) and 

 Procerites schloenbachi by Grossouvre, 1918, (Bull. Soc. G. Fr. (4) XVIII, 

 p. 388). So this lectotype of Procerites schloenbachi, Grossouvre sp., is 

 genotype of Procerites, which covers compressed forms of zigzag origin 

 in which zigzag ornament is soon lost. 



Zigzagiceras, S. Buckman 1902 (Y.T.A. II, 1914, ix). This 

 covers massive forms of zigzag origin in which zigzag stage persists for 

 some time. 



The rapid development of an elaborate s.l. in Zigzagiceratidaj — in 

 small forms with zigzag ornament the s.l. is comparatively simple 

 (S. Buckman, Q.J.G.S., XLVIII, 1892, xiv, 1) — is paralleled by the 

 rapid elaboration of s.l. in other genera, Vermisphinctes, Lepto- 

 sphinctes. Elaboration of s.l. may not necessarily be a reason for 

 parting genera from those which have it poorly developed — such forms 

 may have merely retained the original form of s.l., or they may be 

 phaulomorphs. Again, septal degeneration has to be allowed for — 

 a phenomenon particularly noticeable in certain Perisphinctoids, Prop- 

 lanulites, Pictonia. Comparison should be between what may be called 

 the acinic forms of s.l. of different lineages. 



Family A TA XIOCERA TIDM, nov. 



Distinct from Perisphinctidas as defined above (p. 27) by (1) difference 

 of inner whorls — instead of angulation and morphoceratan sculpture, 

 delay in production of ornament (bradypalingenesis ?) ; (2) longer 

 retention of parabolic curve stage and parabolas perhaps placed more 

 peripherally ; (3) secondary ribs on anamorphs and brephomorphs often 

 rursicostate, passing in later forms to versi- and then to prorsicostate ; 

 (4) s.l. comparatively simple (einfach ; wenig verzweigt ; Siemir.). 



Genera, Biplices, Ataxioceras, Siemiradzkia, Planites, etc. ; Poculi- 

 sphinctes. 



Biplices, v. Sutner-Siemiradzki 1898, (Siemir. p. 77). " a. Muta- 

 tionsreihe d. Per. Tiziani und Colubrimis." Now chosen as genolectotype, 

 P. tiziani (Oppel), Siemiradzki's interpretation, (pp. 147-149). 



Ataxioceras, Fontannes 1879, (Crussol, p. 66, x, 1-4) ; " Peri- 

 sphinctes [Ataxioceras) hypselocyclus." 



" Le terme Ataxioceras a ete imprime pour la premiere fois dans 

 1 'explication de la planche x (fig. 1-4) de la Description des Ammonites 

 des Calcaires du chateau de Crussol (Ardeche) par Fontannes ou il est 

 intercale entre parenthese entre Pcrisphinctes et hypselocyclus. Cette 

 espece est done le type du genre Ataxioceras Fontannes, 1879 " 

 (K. Douville, Bull. Soc. Geol. France (4) X, 1910, p. 734, footnote 2). 



Siemiradzkia, Hyatt 1900 (Eastman-Zittel, Pal. I, p. 582). "Type 

 S. (Amm.) Bakerice d'Orb. sp. (Terr. Jurass. PI. 149, Fig. 1, nor. PI. 148)." 

 Parabolas strongly developed. The sealing of ocular apertures (Morph- 

 oceras pseudo-anceps, CLXXIV) suggests a method of making parabola*. 



Planites, de Haan, see Y.T.A., II, 1913, p. iv. 



Terminology 



See III, 5, 11. Technical terms for well-grown and ill-grown forms 

 are required — that which accords with the normal standard may be 



