CONTRIBDTIONS 'lUWARDS A M ONOGR \PH OF THE PaNDORID^. 



By Philip p. CARrE.xxER, B.A., Ph.D. 



It is remarkable that, notwithstanding the zeal with which most of 

 the old genera have been divided, to meet the wants of modern n.ala- 

 cology, the genus Pandora, Lam., has been left untouched by Dr. 

 Gray, Messrs. Adams, and their follower, Chenu. Yet the species 

 known to the elder Sowerby present three distinct types of hinge, 

 which were well figured by him in his ' Concliological Illustrations.' 

 Specimens and even species of Pandora (except of the well-known 

 N. Atlantic forms) being very rarely seen in collections, it is pre- 

 sumed that naturalists have had but ^tw opportunities of studying 

 them. Mr. Cuming having most kindly allowed me to examine the 

 hinge of all the species in his collection, it has appeared desirable to 

 propose two new genera, and also to group part of the typical species 

 under a subgenus. 



It was at one time thought that the presence of an ossicle in the 

 cartilage was a family mark o{ inatinidcc, to which Myadora from 

 PandoridcB, and Tellimya from Kelliadce, were consequently removed. 

 One of the new genera of Pandorids, however, possesses a well-deve- 

 loped ossicle ; and a small one is seen even in some species of the 

 normal genus. 



The most highly organized structure in the family is found in the 

 North American genus CikUophora, which has both clavicle* and 

 ossicle ; the next is the East- Indian group Coelodon, which wants 

 both clavicle and ossicle, but possesses a tent-shaped dentition in the 

 left valve. The simplest form is the well-known Pandora, which 

 has neither clavicle, tent, nor ossicle ; but in the subgenus Kennerlia 

 the ossicle is present. The genus Myodora is quite distinct, but 

 connected with Pandora through Kennerlia. 



Genus CLiDioPHORAf. 



Testa PandoriformiSyVentraliter expansa ; valva dexfra tridentafa, 

 dente pustico elonyato ; valva sinistra scepius bidentata, dente 

 antico simplici ; cartilagine ossiculo jirmata ; sinu liallii nulla. 



1 . Type, Clidiophora claviculata, Cpr. (^Pandora cl.) P.Z.S. 

 18.55, p. 228. 



* The word " clavicle " is used (in default of a better) to denote a linear dental 

 process runninsi; into the body of the shell, often serving as a support to the car- 

 dinal plate, as in Anatina and some species of Placunoniia. 



t Til. KXeiciov, a clavicle; 0e'pw. 



1.5 225 



