54 TYPE AMMONITES— ill Sept. 



1921 



Further distinction from Parkinsonida; is the failure of Kosmo- 

 ceratidai to produce Perisphinctean forms. Tlie rounded venter crossed 

 by ribs, attained as a late phase by many Kosmoceratids, is the analogue 

 of the Perisphinctean venter ; but, in the Kosmoceratids, inclusion has 

 by then become too great to produce Perisphincteans : platycones or 

 Macrocephalitoids are evolved. Distinction from Macrocephalites is the 

 passage through Kosmoceratid venter, however much this may be masked 

 by later whorls : Macrocephalites has no such phase. 



KOSMOCERAS, Waagen 1869, (Am. subradiatvs ; Geogn.-Pal. Beitr., 

 II (2), 248), Cosmoceras, Auctt. Proposed for the Ornati, all of which 

 named up to that date are therefore genosyntypes. No genolectotype 

 has ,bcen chosen. Take as such Ammonites omatus rotundus, Quenstedt, 

 Ceph., 1840, ix, 19, p. 133, = Kosmoceras rotundum, Quenstedt sp. 

 The genus is thus to be distinguished by somewhat intermittent, rather 

 feeble tuberculation of lateral , area ; by smooth, subsulcatc venter, 

 bordered by strong spines in alternate position ; by suture-line with 

 short EL, rather highly developed and broad Li, fairly long but narrow 

 L2. Germany, England, France, Russia. 



Kepplerites, Neumayr & Uhlig, 1892 (Kaukasus, p. 53), " Typus 

 Kepplerites Keppleri Oppel [sp.] " (p. 55). This leaves it uncertain 

 whether Oppels types or Neumayr & Uhlig's specimen or specimens 

 identified therewith are to be the genoholotypes. Taking all as geno- 

 syntypes, advisable to choose Oppel's large measured example as 

 lectotype of his species and genolectotype of Kepplerites. Though it 

 has not been figured, its dimensions are given : they read as T. 143, 

 3 1 . 35. 35. From them and the description (Pal. Mitth. m, 1862, 157), 

 his species is near to Am. macrocephalus evolutus, Quenstedt, (Aram. 

 Schwab. Jura, 1887, lxxvii, i, F. 133, 36, [38], 33), but loses its runcinate 

 stage earlier. [Lobes broad and short according to this identification.] 

 There are possibly several lineages with somewhat similar characters. 

 Germany ; " Zone des Amm. macrocephalus." England, Cornbrash. 



Sigaloceras, Hyatt, 1900 (Op. cit. p. 587) "Type 5. (Amm.) 

 calloviense, d'Orb. sp." [Terr. jur. Ceph. 1847, clxii, 10, 11, non Am. 

 calloviensis , Sowerby]. A runcinate with fine ornament, costula? sinuous : 

 change over to Macrocephalitoid stage not known. [Suture-line not 

 given, but, presumably, highly developed, with a particularly long EL — 

 about the most florid s.l. of any Kosmoceratid, see T.A. CCLV]. England ; 

 France. 



Gulielmiceras, S. Buckman 1920, Legend of PI. CXCIV ; Geno- 

 holotype, the example of G. gulielmi there figured. A highly ornate 

 platycone, with two rows of lateral tubercles and two rows of short 

 spines bordering a smooth narrow venter. [S.l. simple, with broad, 

 shallow lobes]. Passes into forms with rounded venter, losing ornament. 

 England ; Scotland ? France ; Germany ; Russia ? 



In anamorphs and brephomorphs a venter costate or subcostate 

 between spines is to be expected. Also, in the former, the stage of 

 development of inner row of lateral spines might not be reached. 



GOWERICERAS, 11. Kepplerites Auctt. Am. gowerianus group. 

 Genotype, Gowericeras metorchum, n., T.A. 1921, CCLIV. Distinct from 

 Kepplerites by suture-line — lobes somewhat long and narrow, EL longer 

 than Li — by earlier loss of runcinate stage, by not passing into a Macro- 

 cephalitoid stage, but having rather the aspect of an involute Stepheoceras. 

 England, Scotland ; Kellaway's Clay (a), majesticus. Continental 

 occurrence doubtful : to be expected in Deux Sevres and at Balin. 



