Brachiopod Nomenclature. 323 



iiotod. ]\rost Terebratulids are epitliyrid, but Strinrjocephalus 

 is liypotliyrid ; most Rliynchonollids are liypotliyrid, but 

 Terehraiidoidea is epitliyrid — in other words, it is a Rliyncho- 

 ncllid with a truncate perforate beak. 



The case rejj^ardinp; Cle'wthyris is hardly so satisfactory as 

 the others. Phillips's two statements are : — 



"Cardinal area obsolete; beak incurved over a minute 

 perforation, which is often obtect or merely serves to receive 

 the be-ak of the smaller valve — CJeiothyris. 



" Under the licad of Terehratida 1 shall include many of 

 the Ati'Tjpw of Dalman and Sowerby, givin;^ this term and 

 Cleiothyris as synonyms of a part of that great group. Strigo- 

 cephaliis, Ortliis, and Spiriftra will be separated. In this 

 latter genus 1 include the analogues of Spirifera lineata, and 

 which seem to conduct naturally to the smooth terebratuli- 

 form species now ranked as Atrypa by Mr. Sowerby " (p. 55). 



"The iffect of introducing the classification of Brachiopoda 

 presented on pp. 54, 55, would be a modification of Spirifera 

 and Terehratula by transferring a part of the species here 

 included in these groups to Cleiothyris and Hypothyris. 

 Until, however, the foramen of the larger valve is more 

 carefully examined, in the plaited species analogous to 

 Terehratula pleiirodon, T. pugnus, &c., in the smooth species 

 allied to Terehratula concentrica (von Buch) and Spirifera 

 imhricata (Sowerby), and in those which rank with Tereh. 

 prisca, it seems not desirable to disturb too much the existing 

 methods of classification '' (p. 92). 



The first of these two statements signifies that Cleiothyris 

 is not to replace Atrypa, but is to be used by the side of it, 

 for "the smooth terebratuliform species now ranked as 

 Atrypa by Mr. ISowerby.^' In the next statement there are 

 three divisions made: — (1) '^ plaited species"; (2) "smooth 

 S})ecies " ; (3) " [species] which rank with Tereb. prisca." 

 Obviously, then, Cleiothyris is the term for division 2, and in 

 this are mentioned T'erebratida concentrica (von Buch) and 

 Spirifera imhricata (^owQvhy). It may be argued that by 

 saying Spirifera imhricata Phillips expressed his opinion as 

 to its probable position, and so he left Terthratula concentrica 

 to be the type of his genus. 



There is further evidence for this in the footnote, p. 55. 

 Phillips says " Cleiothyris .... with the terms Epithyris 

 and hypothyris might console us for the loss of Terthratula^ 

 which in von Buch's view includes the three groups.'' 

 Evidently, then, Cleiothyris included a species called by 

 von Buch a Terehratula. 



2^^ 



