BRACHIOPODA 187 



Spirifer, l Rkynckonella. } The first two are confined to the De- 

 vonian. 



Carboniferous. Lingula, Orbiculoidea, Crania, Orthothetes, Cho- 

 netes, Athyris, Ortkis, Spirifer, Syringothyris, Productus, Dielasma, 

 ' Rkynckonella ' {Pugnax, Hypothyris). Spirifer and Productus are 

 particularly abundant. 



Permian. Productus, Stropkalosia, Camarophoria, Spirifer, 

 Dielasma. 



Mesozoic. Most of the important Palaeozoic genera die out 

 before the commencement of the Mesozoic period, but two forms 

 allied to Palaeozoic types are found in the Lias, viz : — SpirifeHna and 

 Cadomella. The Mesozoic period is remarkable for the extraordinary 

 abundance of Terebratida, Magellania, and Rkynckonella. Other 

 genera which occur are Lingula, ' Discina,' Crania, Thecidea, Tere- 

 bratulina, and Terebratella — the last four are more abundant in the 

 Cretaceous than in the Jurassic ; in the former Magas and Kingena 

 also occur. Koninchina is confined to the Trias. 



Tertiary. Brachiopods are very poorly represented ; the follow- 

 ing genera, all of which have living representatives, occur in 

 Tertiary deposits, but are not common : — Lingula, Terebratida, 

 Terebratidina, and Magellania. 



