32G On BracMopod Nomenclature. 



Shells vliynclioiielllform, hypothyrid, with the surface 

 sinuate or feebly semiplicate. 



The genus is nearest to Camarophoria ; it is not one of the 

 Athyridse, but belongs to the family Pentameridae. The 

 later-named Camarophoria may probably be distinguished 

 from it, as containing shells more transverse, more fully and 

 more numerously plicate. 



The species placed in it by M'Coy are rightly classed. 

 Their distinction as three species of Seminula seems to be 

 justifiable ; but three names will be S. jientaedra (Phill.), 

 S. seminula (Phill.), ^S'. rhomhoidea (Phill.). The last is 

 probably quite distinct enough from the Permian T. globulina, 

 which is also a Seminula. 



What has hitherto been called Seminula must be altered, 

 thus : — 



Genus COMPOSITA, Brown, 1845. 



Type Spirifer ambiguus, Sowerby. 



Syn. Seminula, Hall & Clarke, Schuchert et al. ; non Seminula, 

 M'Coy. 



Leptodus, Ltttonia. 



In systematic works the generic name Leptodus, Kayser, is 

 placed as a synonym of Lyttonia, Waagen ; but this is 

 not justifiable. Waagen had no right to give a new name 

 because Kayser happened to place his genus among the fishes. 

 So we must record thus : — 



Genus Leptodus, Kayser, 1883. 



Genoholotype L. Richthofeni, Kayser. 

 Syn. Lyttonia, Waagen. 



Genus Cyclothyeis, M'Coy, 1844. 



Type, the species figured by M'Coy, Carb. Foss. p. 150, fig. 29,= Terebr. 

 latissima, Sowerby. 



Dall says that M'Coy's figure is indeterminable; but this 

 is not justified. It is obviously a multiplicate lihynchonella, 

 and Davidson is quite correct in mentioning Eh. latissima as 

 type. Thus it will be more correct at present to turn over to 

 Cyclothyris the bulk of the present Mesozoic BhynchonelUv — 

 all those which are multiplicate and hypothyrid ; leaving in 

 true l\hi/nchonella only the species which are ]iauciplicate 

 and hypothyrid, congruous with li. lo.iia — such series as the 

 Ji. acuta group. 



