CLASSIFICATION OF THE BRACHIOPODA. 



45 



d'Orbigny, Mr. Sharpe, M. Bouchard, and others. It was also in 1 844 that Dr. Carpenter's 

 first important investigations on the shell structure appeared;^ and in 1846 Professor King 

 proposed to arrange the Palliobuanchiata into ten families and twenty-two genera, viz.r — 



Fam. OfiOLiDiE Genus. Oholus. 

 „ LiNGULiD^. G. Lingula. 



,, ORBicuLiDiE. G. Orbicula. 



„ Calceolid^. G. Calceola. 



„ Strophomenid^. G. Strophomena, Orthis, Leptana^ Ckonetes 



,, Productid.«. G. Productus, Strophalosia. 



„ Terebratulid^. G. Terehratula, Hypothyris, Pentamerus, Camaropkoria, Uncites. 



„ Spiriferid^. G. Spirifer, Atrypa, Martinia, Strigocephalus. 



,, Thecideid^. G. Thecidea. 



in his 'Figures and Desc. of the Pal. Fossils,' p. 54, but the author did not completely apply his 

 own views : 



"Brachiopoda — 



Valves free ; attachment by exserted muscle. 



Valves equal ....... 



Valves unequal ; larger valve imperforate {Athyridee), 



No cardinal area ....... 



A cardinal area ....... 



Large valve perforated in or under the beak. 



Perforation reaching to the hinge line (Delthyridce) 



Cardinal area more or less common to both valves 

 Cardinal area confined to the larger valve. 



Internal plates of the larger valve separate 

 Internal "plates of the larger valve united on the mesial line of the shell. 



Plates narrow ....... 



Plates very broad ....... 



Cardinal area obsolete, beak incurved over a minute perforation, which is 

 often obtect, or merely serves to receive the beak of the smaller valve 



Perforation not reaching to the hinge line {Cyclothyridce") 



Beak truncate, perforate ...... 



Beak acute, the perforation below it ... . 



lAngula. 



Prodvcta. 

 Calceola. 



Orthis. 



Spirifer a. 



Strigocephalus. 

 Pentamerus. 



Cleiothyris.'' 



Epithyris. 

 Hypofhyris. 



°. The difference between Strigocephalus and Pentamerus appears to me not very important! 



' The term Atrypa (a, privative, and rpvna, foramen,) is objectionable ; Cleiothyris (/cXeiw, claudo, 

 6vpa, janua,) would be preferable, and with the terms Epithyris and Hypothyris might console us for the 

 loss of Terehratula, which in Von Buch's view includes the three groups. 



' In the sense of encircled." 



1 Report of the British Association for 1844 and 1847. 



2 Annals and Mag. of Nat. Hist., vol. xviii, p. 83, 1846, at which period the learned Professor likewise 

 published his views on the muscular system in Terehratula. 



