FAMILIES OF LOOP-BEARING BRACHIOPODA 307 



STRINGOCEPHALIN.E Dall. 



Loop long, following the margin of the dorsal valve, not 

 recurved in front. Probably no median coiled arm. 



Stringocephalus Defrance. 



TEREBRATULIN^E Dall. 



Loop usually short. Ascending branches, when present, 

 formed by partial resorption of a primary centronelliform loop. 

 A median unpaired coiled arm exists in recent genera. 



Cryptonella Hall. Terebratulina d'Orbigny. 



Megalanteris Suess. Dictyothyris Douville. 



Dielasma King. Pygope Link. 



Dielasmina Waagen. Goenothyris Douville. 



Liothyrina (Ehlert. G-lossothyris Douville. 



DYSCOLIINJE (= Dyscoliidse Fischer and (Ehlert emend.). 



t 

 Loop short, continuous with the cirrated edge of the lopho- 



phore. No coiled median arm. 



Dyscolia Fischer and (Ehlert. ? Agulhasia King. 



Eucalathis Fischer and (Ehlert. 



Family TEREBRATELLID.E King emend. 



Loop in the higher genera composed of two primary and 

 two secondary lamellae, development indirect, passing through 

 a series of distinct metamorphoses while attached to a dorsal 

 septum. Cirri directed inwardly during larval stages, at 

 which time the structure is comparable to that of Grwynia 

 and Cislella. 



DALLININ^, n. sub-fam. 



Loop composed of descending and ascending lamellae, pass- 

 ing in the highest genera through metamorphoses comparable 

 to the adult structure of Platidia, Ismenia, Muhlfeldtia, 



