m 



SYSTEMATIC 

 See Vol. I, pp. i-viii 



Genus, BEANICERAS, nov. 

 Type, Am. luridus, Simpson (see No. 73). 



A Liparoceratid which attains a capricorn-like stage by development 

 contrary to that of other Capricorn genera : they develop from serpenti- 

 cone (capricorn) to sphaerocone ; but this develops from (tuberculate ?) 

 cadicone to serpenticone. In the other genera the capricorn stage is 

 anagenetic ; in this one it is catagenetic. 



The suture-line shows a marked A-shaped cell parting the peripheral 

 or external lobe. 



The costae not so massive as in other Liparoceratid genera, and the 

 umbilicus flattening out after an early cadicone period are the features 

 of distinction. 



If Am. luridus be rightly interpreted as a development of Am. 

 centaurus, d'Orbigny, then that species represents the spinous cadicone 

 stage ; and the generic definition could read : — Catagenetic series, develop- 

 ing from tuberculate cadicone to costate serpenticone. The likeness 

 of Beaniceras to other Liparoceratid genera, shown by Blake's placing 

 Am. luridus as a synonym of Mgoceras capricornum (Blake, 1876, 281), 

 and by Geyer's similar misidentification of a species of Beaniceras (Geyer, 

 1893, in, 7, 8, 10), is a phenomenon of cyclical homceomorphy, (II, vi). 



Derivation : In honour of W. Bean, of Scarborough, Simpson's 

 contemporary. 



Genus, BIFERICERAS, nov. 

 Type, Bijericeras bijerum, Quenstedt sp. 



A Liparoceratid series distinct from Deroceras on account of its 

 simple suture-line without hanging inner portion ; distinct from other 

 Liparoceratids by its fairly long smooth larval (nepionic) stage ; from 

 the capricorns by not developing sphaerocones. It shews similar, but 

 much slower development than the capricorns ; for the swelling of the 

 whorl in the bituberculate stage is only slight— a feeble rrefiguration 

 of later development in the family. 



The type is cited as above so that an actual genotype may be figured, 

 and there may be no question of misidentification : the figured example 

 to be th^ type. 



Genus, WALKERICERAS, nov. 



Type, Walkeria delicata, S. Buckman 



t A necessary change of name : Walkeria is pre-occupied. The type 

 is m Mon. I. O. Amm., 1904.. Supp]., p. cxl, fig. 122. 



