CLASSIFICATION OF THE BRACHIOPODA. 47 



In the same year M. Barrande divided the Brachiopoda of Bohemia into Terehratula, 

 Stringocephalus, Pentamerus, Thecidea, Spirifer, Orthis, Leptcena, Chonetes, Froductus, 

 Crania, Orbicula, and Lingula} 



In 1848, Dr. Gray proposed his new arrangement/ dividing the class into five orders, 

 which may be analysed as follows: — 



BRACHIOPODA. 1. Sub-Class— ANCYLOPOD A. 



I. Order — Ancylobrachia. 1, Fam. Terebratulida. 



II. Order — Cryptobrachia. 1, Fam. Thecideida (Argiope ««<^ Thecidea). 



2. Sub-Class— HELICTOPODA. 



III. Order — Sclbrobrachia. 1, Fam. Spnriferida ; 2, Fam. BhynchoneUida, Mhyn- 



chonella, Camarophoria, TJncites? Trigonosemus, Rhgnchora, Pggope, Delthyridea, 

 Pentamerus. 



IV. Order — Sarcicobrachia. 1, Fam. Pr'oductida, Productus, Strophalosia, Cho- 



netes, Leptana, Orthis, Strophomena, and Calceola. 



2, Fam. Craniada. 



3, ,, DiscinidcB. 



4, „ LingulidcB. 

 V. Order — Rudistes. 



Dr. Gray's scheme appears objectionable on account of the perhaps uncalled for subdi- 

 vision of the class into five orders ; thus, for example, the second order, Cryptobrachia, 

 seems completely unnecessary. The position of several of the families and genera is also 

 incorrect ; as instances of this we find in Order III, among the Rhynchonellidce, TJncites, 

 whose place is in the Spiriferida ; Trigonosemus, Pygope, Rhynchora, and Belthyridcea, 

 should have been classed in the first order with the Family Terebratulidce^ where Argiope 

 ought likewise to have been admitted. Calceola, quite an anomalous shell among the 

 Brachiopoda, is placed in the same family as Productus, although possessing none of the 

 essential characters of the last-named genus. 



In the 'Index Palaeontologicus,' 1849, M. Bronn divides the class into 29 genera, 

 several of which are, however, only synonyms. 



We now arrive at Professor King's second scheme, where tne learned Palaeontologist 

 adopts three of Dr. Gray's orders, and divides the class into 16 families and 49 genera, as 

 follows : — 



1 ijber die Brachiopoden aus den Naturwissenschaftlichen Abhandlungen, 1847. 



2 Ann. and Mag. of Nat. Hist., vol. ii, p. 435, 1848. 



^ These corrections have been introduced in the Catalogue of the Brachiopoda in the Brit. Mus., 

 1853. 



