254 CARBONIFEROUS LAMELLIBRANCHIATA. 



satisfactorily be placed in any of the accepted families of the Lamellibranchs. 

 These genera have been referred by various authors to various families, including 

 the Mytilidss and the Anatinidae. I have felt it imperative, therefore, to form a new 

 family, and have adopted for it the name proposed by King, Edmondidas, which I 

 would place after the Unionidae. King states of this family, " This is a provi- 

 sional group, supposed to be related to Mytilidae, concluding from the internal 

 cartilage-fulcra, edentulous hinge, and entire pallial line of its type." The type 

 of the genus Edmondia is stated to be Isocardia unioniformis, Phillips. I think 

 that the term "cartilage- fulcra" is misleading, and that de Koninck and de Verneuil 

 were describing something different from that which King called by this name. 

 De Koninck, it seems, was describing a vertical plate, the hinge-plate, but King 

 assumed that he referred to a horizontal ossicle, a character which he (King) 

 figures most accurately in a shell from the Redesdale Ironstone, which, however, 

 differs in every essential character from the type of the genus Edmondia, and 

 which must therefore be referred to a new genus. 



When de Koninck proposed the name Edmondia for his new genus he stated 

 that it belonged to the Madrid as, and at the same time placed Cardiomorpha in 

 the family Cardiadae, notwithstanding the fact that neither of these genera 

 possessed hinge-teeth. He thought that these genera might bear some such 

 relation to the types of those families as Anodon does to Unio ; but the Mactridss 

 are sinuopallial, and Edmondia integropallial. 



King thought that Edmondia showed more affinities to the Mytilidae, but still 

 retained Cardiomorpha in the Carditidae. De Ryckholt referred his new genus 

 Scaldia to the Madridse ; and de Koninck states that he included in it species of 

 Edmondia and Cardiomorpha. 



M'Coy included Edmondia in the family Mytilidae, and Cardiomorpha in a new 

 family, Ccelonotidas, which he placed immediately after the Mytilidae. Edmondia, 

 however, is equi valve, not byssiferous, and has no mytiliform characters whatever. 



Stoliczka placed Edmondia and Cardiomorpha together in a new sub- 

 family, Anatininx, of the Anatinidse, in spite of the absence both of an internal 

 cartilage-pit and the presence of a deeply sinuate pallial line. 



Meek and Hayden place Cardiomorpha and Sedgwickia in the Anatinidse. 



Fischer refers Edmondia to Lyonsiidx, and Cardiomorpha and Sedcjwichia, 

 with a number of very different genera, provisionally to the Grammysiidx ; while 

 Pachydomus is placed in a new family, Pachydoniidx, which is located after the 

 Cyprinidx ; Scaldia and Pseudedmondia are referred to the Unicardidx. 



De Koninck, in his final work on the Carboniferous Lamellibranchs, placed 

 Cardiomorpha, Edmondia, Pachydomus, and Scaldia, with several other very 

 dissimilar groups, in the Anatinidae. 



I do not think it permissible to place any group of shells in the Anatinidae 



