JUKES-BROWNE : SYNOPSIS OF THE VENERID^. 59 



synopsis, but unfortunately this is not the case. The strict application 

 of the rule of priority has created many difficulties and absurdities 

 which were not foreseen by those who drew up the International 

 Code of Rules. A notable instance of such an irrational consequence 

 of the existing rule is that of Callista, for if this name is abandoned 

 the well-known group of shells which it connotes will have to take 

 a subordinate place, the name Macrocallista, which was proposed for 

 a small section of the genus, becoming the generic name, wliile the 

 really typical group would receive the name of Chionella, with an 

 Eocene fossil for its type instead of the well-known recent Venus 

 chioyie, which has always been regarded as its typical example. 



Again, if Bolten's Museum Catalogue is I'ecognized as a scientific 

 publication, and is not excluded from the law of priority, his names 

 would supplant those of Lamarck, which have been in general use for 

 a century or more. Moreover, Bolten's Catalogue gives no definitions 

 of genera or sub-genera, and is absolutely devoid of any scientific 

 value ; while Lamarck's genera were properly discriminated and 

 defined. I liold, therefore, that such a displacement of names is 

 unjust, unnecessary, and inconvenient, and as the Zoological 

 Congress has now resolved that exceptions may be made to the rule 

 of priority I hope that Bolten's Catalogue may soon be declared an 

 exception. 



Meantime I refuse to be bound by the trammels of this rule in 

 the strict fashion which some still advocate. I shall therefore retain 

 the name Callista as used by Morch in 1853 and by the Adams in 1857, 

 ignoring its use by Leach in 1852 with a different signification which 

 can never become operative. Similarly, I shall not accept the revived 

 use of the names Cytherea and Paphia, as proposed by Dr. Dall, who 

 adopts and adapts them from Rolten. 



As I have described most of the fossil groups in previons papers it 

 will suffice for ray present purpose if I mention them in their proper 

 places, with only brief notices of their chief characteristics. The most 

 ancient genera appear to be Callista, Bosiniopsis, Cyprimeria, Flaventia, 

 and haroda, all of whiih are found in the Cretaceous deposits of 

 Europe and India. Pitaria ajjpears in the Eocene, and is probably 

 the ancestor of Dosinia, which does not make its appearance till the 

 Oligocene, and then only in America, the earliest European Dosinia 

 being of Miocene date, though the sub-genus Cordiopsis occurs in the 

 Oligocene. 



Dosiniopsis does not seem to me to have any closer affinity to 

 Dosinia than to Callista, but it is certainly related to Sunetta through 

 the Eocene Meroena; the latter, indeed, might be regarded as a 

 Dosiniopsis in which the posterior lateral teeth have been obliterated 

 by the extreme depression of the posterior border. 



With regard to the shells to which I gave the name of Flaventia 

 in 1908, I am still of opinion that dementia is their nearest living 

 representative, but the group is really a comprehensive or less 

 differentiated type, combining characters now found in Clementia and 

 Samarangia. It may also have been the ancestor of Vefins and Chione, 

 but if so the links have not vet been discovered. 



