CLASS II 



BEACHIOPODA 



383 



Bilohites Linn. (Dicoelosia King) (Fig. 564). Silurian and Lower Devonian ; 

 Europe and North America. 



Schizophoria King (Fig. 565). Relative convexity of valves reversed. 

 Large, very finely striate, with the striae hollow and spinose. Cardinal 



Frc. 5»j5. 

 A-C, Schizophoria strkUida (Schloth.). Devonian ; Gerolstein, Eifel. A, Dorsal aspect. B, Interior of 

 dorsal valve. C, Interior of ventral valve. D, S. rnlviirin (Schloth.). Spiriferensand.stein (Late Lower 

 Devonian); Xiederlahnstein, Nassau. Internal mould. (All tigures of the natural size.) 



process in mature shells with accessory ridges making it multilobate. Dorsal 

 interior marked by 4 to 6 deep pallial sinuses. Silurian to Coal Measures ; 

 widely distributed throughout the world. Subgenus : Orthotkhia Hall and 

 Clarke. Like Schizophoria externally, but in the ventral valve the dental 

 lamellae and a median septum are highly developed. Coal Measures ; Brazil 

 and India. 



Subfamily C. 



Enteletinae Waageii. 



Rhipidomellidae with decidedly convex valves and a few broad plications super- 

 added to the very fine radial striae. Developed out of Orthotichia. 



Enteletes Fischer (Syntrielasma Meek and Worthen). Dorsal valve more 

 convex than ventral. Hinge-line short with a high ventral cardinal area. In 

 the ventral valve the dental lamellae are high and convergent, and between 

 them is a marked median septum ; the crural septa of the dorsal valve are 

 also well developed. Coal Measures and Permian ; North and South America, 

 Europe and Asia. 



Enteletoides Stuckenberg. Upper Carboniferous ; Russia. 



Superfamily 2. STROPHOMENACEA Schuchert. 



Progressive, terminal Protremata, derived out of Orthacea (Billing sellidae), with- 

 out spondylia and cruralia. Deltidia and chilidia nearly always present throughout 

 life ; cardinal process always tvell developed. Pedicle nearly always small, emerging 

 through the apex of the valve, or lost when the shells cement to foreign objects or anchor 

 by means of ventral spines. A prolific stock of Brachiopods. Ordovician to Recent. 



Family 1. Strophoraenidae King. 



Primitive Strophomenacea with well -developed deltidia and chilidia. Shells 

 usually flat or concavo-convex and hut rarely biconvex. Pedicle usually functional 

 but tending to be thin and weak, and often lost when the shells cement to foreign 

 objects or are otherwise held to the substratum {tisually by spines). Ordovician to 

 Permian. 



