CLASS TT 



BRACHIOPODA 



403 



Girtyella Weller. Like Dielasma, but the cruralium is supported by a 

 septum. Lower Carboniferous ; North America. 



Dielasmoides Weller. Like Girtyella, but with septal plates instead of 

 crural lamellae. Lower Carboniferous ; North America. 



Cranaeiui Hall and Clarke. Dental lamellae strong. Socket plates 

 uniting into a hinge-plate which is posteriorly perf orate ; no cruralium. 

 Devonian and Lower Carboniferous. Subgenera : Hamburgia and Dielasmella 

 Weller. Lower Carboniferous, North America. 



Dielasmina Waagen. Plicated Dielasmids. Carboniferous ; India. 



Beecheria Hall and Clarke. Like Dielasma, but without dental lamellae ; 

 cruralium completely sessile. Carboniferous ; North America and India. 



Bowleyella Weller. Both valves with median septa. Lower Carboniferous ; 



North America. 



Heterelasma Girty. 



Smooth Dielasmids with a ventral fold and a dorsal 



smus. 

 Texas. 



Median septa in both valves. Hinge-plate rudimentary. Permian ; 



Hemiptychina Waagen. Plicated Dielasmids without dental plates. Carboni- 

 ferous to Permian ; India. 



Notothjris Waagen (Eostranteris Gemmellaro). Coarsely plicate biconvex 

 Shells with a perforate hinge-plate as in Centronella. Permian ; India. 



Subfamily C. Terebratülinae Dali. 



A median unpaired coiled arm 



Post-Paleozoic TerehratuUdae with a short loop. 

 exists in Recent genera. Triassic to Recent. 



Terehratula Müller 1776 (as redefined by Buckman 1907) (Fig. 599). 

 Genotype Anomia terehra- 

 tula Linn. Pliocene. Large 

 biplicate shells of the Ter- 

 tiary of Europe. 



Musculus Quenstedt. 

 Buckman states that this 

 term will be useful for the 

 Cretaceous biplicate species. 

 Genotype Terehratula acuta 

 Quenst. Europe. 



Epithyris Phillips, non 

 King. Buckman uses this 

 genus for a small group 

 of Jurassic biplicate forms. 

 Genotype Terehratula maxil- 

 lata Sowerby. Europe. 



Ehaetina and Zugmeyeria Waagen. These genera comprise biplicate 

 forms. Trias ; Europe. 



Pygope Link (Diphyites Schröter) (Fig. 600); Antinomia Catullo ; and 

 Pygites de Haan (as redefined by Buckman 1906). Three independent genera, 

 according to Buckman, with the shells originally bilobed, the two lobes often 

 uniting anteriorly in adult specimens, but leaving posteriorly a median 

 hollow Space passing through both valves. Developed out of a Glossothyrid- 

 like form. Jurassic ; Europe. 



Fig. 599. 



Terehratula phillipsi 

 Morris. Middle Jura ; Egg, 

 near Aarau, Switzerland. i/i. 



Pygope diphya (Colonna). Tithonian ; 

 Trent, Tyrol. l/l- 



