668 



MOLLUSCA 



PHYLÜM Vll 



The Cosmoceratidae are probably a polyphyletic group, derived from severalj 

 branclies of tlie Steplianoceratidae. 



Subfamily A. Cosmocbratinae Hyatt. 



Discoidal and involute forms having at a comparatively early stage or throughout 



life two or tbree rows of large tubercles 

 ■■^^ nf^7J?j)»«a Qj^ gg^(3i-^ gi(je^ and costae interrupted on 



the venter by a sniooth median zone or 

 Channel. 



Gosmoceras Waagen (Fig. 1300). 

 Middle Lias to Oxfordian. 



Subfamily B. Hoplitinae Hyatt. 



Discoidal and involute forms with 

 costae bifurcated on the sides at umbilical 



Fio. 1300. 



Gosmoceras ornatum (Sowb.). Callovian (Ornaten 

 thon) ; Gamiuelsliausen, Würteniberg. 



Fit;. 1301 



Hoplites tuberculatus (Sowb.). 

 Gault ; Folkestone, England 

 Siphuncle broken away f 



Fig. 1302. 



Uoplites noricus (Sowb.). i = Ho2Mtes amUygonius Neum,). Neocoraian ; 



Achim, near Börsuni, Prussia. 



Shoulders ; prominent tubercles at their forks, and also at or near their ventral 

 termini, these last being separated by a median zone or deep Channel. Young of 

 some species have costae continuous across the venter, and resemble those of Sonneratia. 

 Parallelism with Cosmoceratinae very close. Sutures resemble those of Mammites, 

 but more complex. Lateral saddles narrower and more deeply cut, and first lateral 

 saddles often trifid in late stages. Dorsal series with two pairs of complex zygous 

 lobes and saddles on either side of a long, narrow, complex, antisiphonal lobe. 



Hoplites Neum. (Figs. 1301, 1302); Genomanites Hang {Discoceras Kossmat) ; 

 Sonneratia Bayle ; Neocomites Uhlig. Cretaceous. 



