DENCKMANNIA i* 



Genus, ECHIOCERAS, Bayle 



1878, Explic. Carte Geol. France, IV, Explan. PI. lxxvii 

 Type E rarecostatum ; Bayle, now E. raricostatoides, Vadasz sp. 

 Serpenticones which develop carination. The nepionic stage with 

 small dose-set ribs is a distinctive feature : it suggests derivation from 

 ;, densiparvulicostate Capricorn like the costate (neanic) stage of 

 liijcriccras. List of species pp. 96c, d ; but further division may be 

 possible Some forms have broad, short lobes like Gagahceras, but not 

 its style of larval ribbing; others have somewhat narrow, long lobes— 

 E. cereum, Y.T.A. 49. 



Am. raricostatus, Zieten, is presumably not an hchioceras. 



Genus, PARECHIOCERAS, nov. 



Type, Am. finitimns, Bean-Blake, Y.T.A. 100. 



Serpenticones like Echioceras, but the nepionic stage has bead-like 

 ribs of Gagaticeras pattern, indicating origin different from Echioceras. 

 Sut ure-line is of Gagaticeras pattern. Keel is developed at an early 

 stage, joining up ribs V-shaped on periphery — features of distinction 

 from both Echioceras and Gagaticeras. Family, Echioceratidae. 



Genus, PROCERITES, Siemiradzki 



1898, Mon. Perisph. 78. 



" Grosse formen welche sich an Per. procerus und Per. congener 

 anschliesen." 



No type selected here or in pp. 303 et seqq. ; but from name, Am. 

 procerus, Seebach (Siemiradzki), should be type. Development stated 

 to be from Stephanoceras zigzag ; but that species is not described as 

 a species of Procerites. 



Genus, ZIGZAGICERAS, S. Buckman. 



1902, Emend. Amm. Nom. 7. 

 " Type. Am. zigzag, d'Orb." Should now be restricted to the 

 stouter form, PI. cxxix, 11, to be followed by Z. crassizigzag. S. Buckman 

 sp., (1890, xiv, 2, 3). This genus would then mark massive species 

 with long-continued zigzag pattern, followed by their stout macro- 

 oephaloid developments, while Procerites would denote the compressed 

 series, which soon lost the zigzag pattern. Intermediate series may yet 

 require separation, for zigzag is a trunk from which arose many branches. 

 At different times these acquired planulate (or perisphinctean) style of 

 ornament (catagenesis from 5 to 4), correlated, however, with differences 

 of thickness, involution, etc. 



Genus, HAUGIA, S. Buckman 



1888, Mon. I.O. Amm., p. 45, note 3. 

 " Type Am. variabilis, d'Orbigny, Ceph. pi. 113, figs 1, 2." 



Genus, DENCKMANNIA, S. Buckman. 



1898, Mon. I.O. Amm.; Sup. p. xvii 

 Type : Denckmannia tumejacta, sp. n." 



