CLASS V 



CEPHALOPODA 



663 



more nearly t'qual. Dorsal sutures generally have three pairs of zygous saddles and 



two pairs of lobes in the coronate discoidal 



forms. 



Stcjihanoceras Neum. (Fig. 1285); Gado- 

 mites Mun.-Chalms. ; Sphaeroceras Bayle (Fig. 

 1281); Eniileia Bucknian ; Normannites 

 Mun.-Chalnias (Fig. 1282); Macrocivphalites MSt^ / 

 Sutner (Fig. 1283); Sutneria Zittel (Fig. 1284). 

 Inferior Oolite. 



. 12.S4. 



Siitiirria platynotii (llfnn.). Upper 

 Juni (Ti'iiiiilobatu.s Buds) ; Balinyen, 

 Wiirteiiiberif. 



Stejihanocerns coronatus (Brug.). C'allovian : 

 Dept. Niovre, France. V;;. 



Subfamily C. Cadoceratinae Hyatt. 



More specialised, compressed, and involute forms tend to evolve shells with 

 creniilated keels, and sometimes channels also. Costae of Cadoceras divided as in 

 Stephanoceratinae, but other genera usually develop two lines of tubercles. Young 

 of Neumayria more or less costated, but sides and keel become smooth, and in some 

 .sijecies resemble the adult of Qnensfedtoceras. 



This group is remarkablo for tlie closo parallelism of some of its genera with Aiualtheidae, 

 but the young are very distinct. Development and adult stages of Cadoceras with its discoidal 

 and much depressed volutions plainly show derivation from Coeloccran stock, while its form 

 and sutures also show relationshi[) with Stephanoceratinae. 



Cadoceras Fischer ; Quenstedtoceras Hyatt ; Gardioccras Neumayr and Uhlig ; 

 Neumayria Nikitin. Kelloway. 



Subfandly D. Perlsphinctinae Steinmann.i 



An extensive series of discoidal genera having rounded or subquadrangular 

 volutions, and costae single on the sides, but split into two, three or more on the 

 venter, which they cross uninterruptedly. Splitting does not begin as a rule at 

 umbilical shoulders, but near the ventro-lateral angles. Inner parts of sutures steeply 

 inclined apicad, and dorsal sutures have a long pair of first dorsal saddles, usually two 

 additional pairs of saddles, and two pairs of lobes. All of these are so decidedly 

 inclined apicad that they often appear as a single pair of complex saddles. 



These genera are morphic equivalents of the Liassic Dactylioidina6 and are derived from 

 the same common stock. Young have depressed trapezoidal volutions and often nunute 

 tubercles on ventro-lateral angles, but are otherwise smooth, like the young of Cadoceras 

 sablaeve. They become compressed in the neanic stage and rapidly assume the discoidal 

 Perisphinctean form and costae without tubercles. 



Perisplmides Waagen {Grossbuvria, Procerites, Ghoffatia Siemirad.) (Figs. 1286- 



vol 



^ Siemiradzki, ./., Monographische Beschreilnuig der Gattung Perisphinctes. Palaeontogr. 1898, 

 , xlv. See also R. DuavtlU's recent studies of Cardioceras, etc., 1913. 



