338 



MOLLUSCOIDEA BRACHIOPODA 



SUB-KINGDOM V 



FIG. 579. 



Parazyga, Hall and Clarke (Fig. 579). Like Trematospira, but with the 

 fine, simple ribs covered with very delicate, shqrt, hair-like spines. De- 

 vonian ; North America. 



Eumetria, Hall. Elongate terebratuliform shells with numerous fine 

 radiating striae. Hinge-line short. Dorsal hinge-plate very complicated. 

 Jugum similar to that of Metzia, but the terminally 

 bifurcated process is extended backward at an abrupt 

 angle, and terminates just in front of the apices of the 

 primary lamellae. Shell structure punctate. Lower 

 Carboniferous ; North America and Europe. 



Acambona, White. Carboniferous ; North America. 



Hindella, Davidson (1 WTiitfaldella, Hall and Clarke). 

 Ovate or elongate, sub-equally convex, smooth, Athyroid 

 shells. The V-shaped jugum has a short, acute process. 

 A dorsal median septum present. Silurian and De- 

 vonian ; North America. 



Hyattella, H. and C. Similar to JHiitfieldella, but 

 compactly sub - pentahedral, and without the dorsal 

 median septum. Silurian ; North America. 



parazygahirsuta,UM. De- Nudeospira, Hall (Fig. 580). Sub-circular, biconvex 

 tuck" 1 '4 Siofthe natural sne ^ s w ^ tn numerous, fine, short spinules. Jugum with 

 size. 'B, 'same with dorsal a long, straight, simple process. Silurian to Lower 

 Carboniferous; North America and Europe. 



Anoplotheca, Sandberger (Bifida, Davidson). Concavo- 

 convex small shells with few plications, crossed by fine, 

 often imbricating growth lines. Jugum originating near the mid-length of 

 the primary lamellae, uniting and forming a simple upright stem articulating 

 in a cavity in the ventral valve. Dorsal 

 valve with a high median septum. De- 

 vonian ; Germany and France. 



Coelospira, Hall (Leptocoelia, Hall). 

 Shells externally much like Atrypa, but 

 with laterally directed spirals. Jugum 

 similar to that of Anoplotheca. Silurian 

 and Devonian; America, Europe, and 

 South Africa. 



Anabia, Clarke. Similar to Coelo- 

 spira, but with a highly convex dorsal 

 valve. Silurian; Brazil, 



Vitulina, Hall. Like Coelospira, but 

 with few plications and a long hinge -line. Plications covered with fine 

 radiating lines or rows of pustules. Devonian ; America and South Africa. 



line of ventral valve, enlarged 

 (after Hall). 



FIG. 580. 



Nudeospira pisum, Sow. Silurian ; Wenlock, Eng- 

 land. A, Interior of dorsal valve. B, Vertical 

 section through both valves, 5/ 2 (after Davidson). 



Biconvex, smooth-shelled 

 Silurian ; North America 



Meristina (WTiitfieldia, Davidson), (Fig. 581). 

 Athyroids. Jugal stem with a short bifurcation, 

 and Europe. 



Glassina, Hall and Clarke. Like Meristina, but with the bifurcations of 

 the jugum originating directly from its apex. Silurian ; England. 



Athyris, M'Coy (Spirigera, d'Orbigny ; Euthyris, Quenstedt), (Fig. 582). 



