FAMILIES OF LOOP-BEARING BRACHIOPODA 307 



Stbingocephalin^ Dall. 



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

 recurved in front. Probably no median coiled arm. 



String ocephalus Defrance. 



Tekebratulin^ 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. Terehratulina d'Orbigny. 



Megalanteris Suess. Dictyothyris Douville. 



Dielasma King. Pygope Link. 



Dielasmina Waagen. Coenothyris Douville. 



Liothyrina CEhlert. Glossothyris Douville. 



Dyscoliin^ (rr Dyscoliidae Fischer and ffihlert emend.'). 



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

 phore. No coiled median arm. 



Dyscolia Fischer and Q^hlert. ? Agulhasia King. 



Eucalathis Fischer and Q^^hlert. 



Family Terebratellid^ King emend. 



Loop in the higher genera composed of two primary and 

 two secondary lamellte, 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 Gwynia 

 and Cisiella. 



Dallinin^e, n. sub-fam. 



Loop composed of descending and ascending lamellae, jiass- 

 ing in the highest genera through metamorphoses comparable 

 to the adult structure of Platidia, Ismenia, Milhlfeldtia, 



