46 INTRODUCTION. 



And in the same year, Mr. Morris published his interesting paper on the subdivision of 

 the Terebratuhe} 



In 1847, M. d'Orbigny presented his views on the classification of the Brachiopoda," 

 chiefly founded on the presence or supposed absence of labial appendages in some of the 

 species, and therefore divides the class into two orders, I. Brachid^ ; II. Cirrhid^e; but 

 from perhaps not having been able to study the animal of Argiope and Thecidea, or mis- 

 taking the brachial disk of the two last-named genera for the mantle, unites them most 

 improperly to the Rudistes which constitute his second order; both Argiojpe and Thecidea 

 are essentially related to the Terebratulida, or to his first division of True Brachiopoda. 

 M. d'Orbigny's arrangement is as follows : — 



I. ORDER— BRACHIOPODES BRACHIDES {Brachidce). 

 1. Earn. LiNGULiDiE. Genus 1, Lingula; 2, Obolus. 

 CALCEOLiDiE. G. 1, Colceola. 



Prodtjctid^. G. 1, Productus; 2, Chonetes; 3, Leptcena. 

 Orthisid^. G. 1, Strophomena; 2, Orthisina; 3, Orthis. 

 RHYNCHONELLiDiE. G. 1, Hemithyris ; 2, Rhynchonella; 3, Striyocephahs ; 



4, Porambonites. 

 Uncitid^. G. 1, Uncites; 2, Atrypa; 3, Pentamerus. 



Spiriferid^. Gi.\,Cyrtia,'i,8pirifer; 2>,Spiriferina; ^,Spirigerina; ^,Spiriyera. 

 Magasid^. G. ], Mayas ; 2, TerebratuUna. 



TEREBRATULiDiE. G. 1, Tcrebatula; 2, Terebratella ; 3, Terebrirostra; 



4, Fissurirostra. 



10. „ Orbiculid^. G, 1, Siphonotreta; 2, Orbicella; 3, Orbiculoidea ; 4, Orbicula. 



11. .. Cranidze. 1, Crania. 



II. ORDER— BRACHIOPODES {Cirrhidce). 



1. Fam. Thecid^. G. 1, Megathyris; 2, Thecidea. 



2. „ Caprinid^e. G. 1, Hijjpurites; 2, Caprina; 3, Caprinula; 4, Caprinella. 



3. „ Radiolid^. G. 1, Badiolites; 2, Biradiolites ; 3, Caprotina. 



In this plan, besides the very objectionable and wide separation of Argiope (= Mega- 

 thyris^ and Thecidium from the Terebratulida, the position of Stringocephalus is certainly 

 out of place in the Family Bhynchonellidce, where the author might have admitted Penta- 

 merus, and by placing Uncites and Atrypa (Dalman) in the Family Spiriferidm would have 

 dispensed with his 6th division. Magas and TerebratuUna should likewise have been 

 added to the Terebratulidce. 



1 Quarterly Journal of the Geol. Soc, vol. ii, p. 382, 1846. 



2 Comptes rendus de I'Acad. des Sciences, 1847. — Ann. des Sc. Nat., 3d series, Zool., vol. viii, p. 141, 

 pi. vii, 1848. — Paleont, Fran9. Ter. Cr^taces, vol. iv, p. 281, 1848. — Cours Elementaire de Pal., vol. ii, 

 p. 79, 1852; and Prodrome. 



2. 

 3. 

 4. 

 5. 



6. 



7. 



