556 MOLLUSCA SUB-KINGDOM vi 



Family 1. Lecanitidae. Primitive discoidal shells like those of 

 with short rounded entire saddles and lobes like those of Ibergiceras, but ventral lobes 

 divided by short, comparatively 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 increased. Antisiphonal lobe entire, and often long and acute. 

 The zygous dorsal lobes are very slight so far as known, and entire ; merely marginals 

 in the dorsal saddles. 



Paralecanites, Diener ; Lecanites, Mojs. ; Ky mat-it es, Parakymatiteg, Waagen ; 

 Proavites, Arthaber. Trias. 



Family 2. Badiotitidae. Discoidal and involute shells similar to Lecanitex, 

 especially in the dorsal sutures, 1m t with well -denned costae and keeled venters, 

 Includes Badiotites, Mojs. (Fig. 1140), and Doricranites, Hyatt. 

 Trias. 



Family 3. Flemingitidae. A provisional group of discoidal 

 forms having longitudinal ridges as in Cladiscitidae. The char- 

 acteristics of Wyomingites connect it apparently with Lecanitidae, 

 while in Flemingites the saddles are long and have a monophyllic 

 aspect. There are, however, no truly monophyllic saddles at any 

 Badiotites Eryt, stage so far as known. The suture lines do not have the inner 



Miinst. sp. Keuper ; extensions common in Gvronitidae. Antisiphoiial lobe bifid, its 

 St. Cassian, Tyrol. 



sides entire, and zygous dorsal inflections limited in number ; but 



the lobes are very broad, and their marginal saddles pointed, irregular in size. 



Xenodiscus, Xenaspis, Flemingites, Waagen ; Wyommgvtes y gen. nov. Type JJ'. 

 (Meekoc.) aplanatum, White sp. Permian and Trias. 



Family 4. Meekoceratidae. Waagen (pars). Shells smooth, compressed, dis- 

 coidal, 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 r 

 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 Gyronites, 

 where they are narrow and pointed as in Lecanitidae. Saddles entire and generally 

 somewhat elongated and linguiform, but plainly of the Lecanites type. Antisiphoiial 

 lobe, so far as known, long, narrow, and bifid so far as known. Extremities of dorsal 

 sutures produced and corresponding with inner parts of external sutures. 



Meekoceras, Hyatt; Nicomedites, Toula; Prionolobus, Gyronites, Beyrichites, Koninck- 

 ites, Kingites, Aspidites, ProptycJntes, Clypites, Paranorites, Waagen ; Apleuroceras, 

 gen. nov. Type A. (Cerat.) Sturi, Mojs. sp. Trias. 



Family 5. Prionitidae. Similar to Gyronitidae, but nodes, when they occur, 

 are larger, and sutures have more or less pointed siphonal saddles, Avhich are usually 

 divided by a siphonal lobe. Dorsal sutures, so far as known, have fewer inflections 

 and different outlines. 



Ophiceras, Griesb. ; Vishnuites, Diener ; Prionites, Goniodiscus, Waagen ; Aploco- 

 ceras, gen. nov. Type A. (Din.) avisianus, Mojs. sp. Plococeras, gen. nov. Type P. 

 (Din.) dalmatianus, Mojs. sp. Diaplococeras, gen. nov. Type D. (Din.) liccanus, Mojs. 

 sp. Trias. Protophiceras, gen. nov. Type P. (Danub.) Nicolai, Diener. Trias. 



II. AEGOCERATIDA. 



Apparently connected through primitive forms with Protophicera*, tiltJuunjlt. xn tares of 

 later stages in most forms depart widely from the discocampylic outline, and are quite 

 similar to those of Pinacoceratidae. The auxiliary series, however, is highly inclined 

 apicad as a rule, and develops differently. There are no adventitious infections. 



