644 



MOLLUSCA 



the dorsal (antisiphonal) lohe 'is undivided in the most primitive 



B 



PHYLUM VI 



forms, and hifid in the 

 more syedalised groups. 



The entire family 

 is supposed to have 

 beeil derived from 

 Lecanites, and tlirough 

 tliat geiius to liave been 

 connected witli Nomis- 

 moceras of tlie Carboni- 

 ferous, and Gephyroceras 

 of the Devonian. 



Fig. 1225. 



Cladiftcitrs tornatus (Bronn). Upper Trias ; Steinbergkogel, near Hallstadt, Austria. 

 A, B, Lateral and anterior views. (', Suture-line. 



Subfamily A. Lecanitinae Hyatt, 



Primitive discoidal Shells like those of the Prolecanitidae, with short rounded entire 

 saddles and lobes like those of Prolecanites, but ventral lobes divided by short coin- 

 paratively broad and entire siphonal saddles. There are all 

 stages in the development of these saddles, so that their 

 aspect is rather' variable. There are as a rule but two 

 principal lateral saddles and lobes, with one auxiliary saddle 

 and shallow lobe on either side in primitive species, but in 

 others the number of auxiliaries may be considerably iii- 

 creased. Antisiphonal lobe entire, and often 

 long and acute. The zygous dorsal lobes are 

 very sliglit so far as known, and entire ; 

 merely marginals in the dorsal saddles. 



Paralecanites Diener (Fig. 1226). Per- 



iiiian and Triassic. Lecanites Mojs. ; Kyma- 



tites, Parakymatites Waagen ; Proavites 



eryx Arthaber; Badiotites Mojsisovics (Fig. 122V). 



Trias. 



Fig. 1226. 



Fig. 1227. 



H. 



Paraleamites arnoldi 

 and S. Lower Trias ; Idaho 

 (after Hyatt and Smith). 



Badiotites 

 (Münst.). Keui)er 

 St. Cassian, Tyrol. 



Subfamily B. Meekoceratinae Waagen. 



Shells smooth, compressed, discoidal and involute, and as a rule with narrow and 

 more or less flattened venter. Sutures in many forms have a tendency to extend the 

 inner lateral saddles or lobes, and to develop a corresponding series of auxiliaries -, 

 and this is carried to an excessive extent among some highly involute shells. The 

 ventral lobes, however, are apt to remain broad and shallow; their arms become 

 highly denticulated except in the Lecanitinae where they are narrow and rounded. 

 Saddles entire and generally somewhat elongate and linguiform, but plainly of the 

 Lecanites type. Antisiphonal lobe, so far as known, long, narrow and bifid. Ex- 



