OKI.KK in TELEODESMACEA 395 



Trapezium (Humph.), Megerle (Libitina, Schum. ; Cyprirdnlin, him. Sln-11 

 Imitate, trape/oidal, ( mi, -rut rically, or more rarely radially .-nilpt mvd, often with a 

 posterior keel; three cardinal Ict-ili in each valve, the posterior in tin- right valve 

 often bifid. Jura to Recent. 



Plesiocyprina, Mun.-Chalm. Jura. Cicatrea, Stol. Cretaceous. Coralliophaya, 

 lilainv. Tertiary and Recent. 



Arctica, Schum. (Cyprina, Lam.), (Fig. 702). Oval or rounded, inflated, concen- 

 trically striated; beaks prominent, curved, cardinals tin re in each valve, the left 

 posterior often bifid, the middle left cardinal largest, and the posterior ridge-like. 

 Abundant in the Jura and Cretaceous, and represented by one or two living 

 species. 



Venilicardia, Stol. (Fig. 703). Cretaceous. Pygocardia, Miin.-Chalin. Tertiary. 



Veniella, Stol. (Venilia, Morton; (?) Goniosoma, Conr.), (Fig. 704). Left valve 

 with the anterior cardinal strong, sub-triangular. Cretaceous and Tertiary. 



Superfamily 2. ASTARTACEA. Ball. 



Lobes of the mantle free ventrally ; lateral laminae obscure, when present distant 

 from the cardinals. 



Family 3. Curtonotidae. Dall. 



Shell short and heavy, with sub-terminal beaks ; valves free, equal, closed ; area 

 obscure ; ligament as in the Astartidae ; adductor scars, especially the anterior, deep ; 

 pallial line simple; hinge plate broad, without lateral laminae; the formula of the 



cardinals I- or J^ 010 . Devonian and Carboniferous. 



This group is inserted conformably with the opinion of Neumayr, who regards it as the 

 radical of the Astartidae. 



Curtonotus, Salter. Oval, cardinal border thick, with one very strong tooth in the 

 left, and a strong anterior and thin posterior tooth in the right valve. Scars of the 

 adductors strong, especially the anterior. Devonian ; England. 



Prosocoelus, Keferst. Devonian. Protoschizodus, de Kon. Carlxmiferous. 



Family 4. Astartidae. D'Orbigny (emend.) 



Shell substance cellulo-crystalline, with a pronounced epidermis; shell rounded or 

 sub-triangular, usually with concentric or not radial sculpture ; valves equal or sub-equal, 

 free, closed ; area distinct ; ligament and resilium external, parivincular, opisthodetic ; 

 beaks prosocoelous ; adductor scars sub-equal, with a distinct anterior pedal scar ; pallial 

 line simple; hinge plate distinct, hinge with anterior and posterior 

 lateral teeth and their respective sockets, usually more or less obsolete; 

 cardinal teeth not bifid at the summit, the terminal teeth frequently 

 obsolete. Lobes of the mantle free ventrally, not produced into siphons. 

 Trias to Recent. FIG 705 



Astarte, Sow. (Crassina, Lam.), (Fig. 705). Roundly triangular Astarte Voitzi, 

 or oval, rather compressed, thick ; smooth or concentrically sculptured ; 

 lunule impressed ; right anterior cardinal strong. Alsace. 



A number of genera have been associated with Astarte which probably belong elsewhere. 

 The following sub-genera, however, are worthy of recognition : Coclastarte, Bohm ; Preconia, 

 Stol. ; Crassinella, Bayle non Guppy (Fig. 706) ; Prorokia, Bohm. Jura. Eriphyla, Gabb. 

 Cretaceous. Grotriania, Speyer ; Goodallia, Turton (Fig. 708) ; Hhectocyma, Dall ; Woodia, 

 Deshayes (Fig. 707). Tertiary and Recent. 



