NORTHUMBERLAND AND DURHAM. 2G9 



24. CARDIOMORPHA, Koninck. 



1. C. Pallasi, De Verneuil. 



It has been proposed by Baron Schaurotb to unite this species 

 witli tlie Modiola Pallasi^ De Vern., and after examining some 

 German specimens with which he has kindly favoured me, and 

 ascertaining from some of Mr. Kirkby's specimens that the hinge 

 is really toothless, I fully. agree with this identification. 



Baron Schauroth has placed it in the genus CleidopJiorus, Hall ; 

 but Mr. King has, I think, more correctly referred it to Cardio- 

 mo7'2^ha, De Koninck. 



In one of Mr Kirkby's specimens, the ligament, which is finely 

 preserved, is comparatively large. Some specimens of the same 

 shell from the equivalent deposit of Pcissneck have the liga- 

 ment in a fine state of preservation. 



It is found in the shell-limestone only, where, sometimes asso- 

 ciated with its congener, M. costata, it is rather plentiful. 



25. MYA CITES, ScMotJieim. 



1. M. lunulata, Keyserling, sp. 



" Schlotheim's name, Mf/acites " (writes Mr. King, " Perm. 

 Mon." p. 196), " implies that the shells so called are fossil Myas: 

 as this is not the case, the name cannot stand." x\nd just above 

 this note the same author states, that " the name (^Allorismci) was 

 proposed under the persuasion that the cartilage-fulcra of the 

 genus varied in position according to the species. This is now 

 known to be an error ; the name is, however, still retained, not- 

 withstanding its being a misnomer." The conclusiveness of this 

 reasoning seems to have had its effect upon all careful English 

 naturalists, for I find Mijacites now adopted, and Allorisma con- 

 signed to mere oblivion. It still, however, lingers on the Conti- 

 nent, shortly to become for ever extinct. 



There can be little doubt about the identity of King's A. eh- 

 gans and the Amjjhidesina Iwmlata, Keyserling. Even Mr* 

 King himself seems disposed to admit this. This being so, the 

 latter name for the species must be adopted, because the three 



VOL. 111. I'T. IV. 1 K 



