Z CATALOGUE OF 



Dall selects the unknown Tellina pusiUa, Gmelin, as the type, 

 instead of any of the forms included by Ferussac, one can only 

 regret that, doubtless with the best intentions, the distinguished 

 American Conchologist should have further complicated zoological 

 nomenclature by endeavouring to resuscitate such a mere tentative 

 sectional designation. To set aside Pfeiffer's name, deliberately 

 chosen to designate a group of species having a good common 

 character, in favour of a subgeneric term, that can only be retained 

 for certain of its incidental members by a somewhat arbitrary 

 manipulation, is to stretch the much abused law of priority to its 

 breaking point, and in this Catalogue, therefore, Pfeiffer's name 

 Pisidium will be adhered to. 



In 1820 Rafinesque (146) used Pliymesoda* for one of his 

 divisions of the genus Cydas, his types being " C. lacustris 

 (f=.SpJicerium\ C. dubia, Say, &c." Dall, in spite of its mixed 

 character and faulty definition, revives the name for a section of 

 his Corneocyclas, taking however as type, Tellina virginica, Gmelin 

 (p. 3236, no. 39), which is held to have priority over Say's 

 C. dubia t though what Gmelin's species really was is more than 

 doubtful. 



The synonymy of the genus is : 



Pisidium. C. Pfeiffer, Naturg. Deutsch., Moll. Abtlil. i, 1821, pp. 17 



& 1237 - 

 Pisum, "Megerle, 1811 ; non Linn." : Gray, Proc. Zool. Soc. Lond. 



xv, 1847, p. 184. 

 Galileia, O. G. Costa, Fauna Sicilia, Mollusclii, p. 1, pi. i, fig. 2 a, 



A, B (1840). 



Pern* 8 "' Leach, Syn. Moll. Gt. Brit. 1852, pp. 291-2. 

 Cordula, 



Musculium. Link : II. & A. Adams, Gen. Recent Moll, ii, 1858, 

 p. 451 (non Link). 



With regard to Galihia, 0. G. Costa (sometimes misquoted as 

 "Da Costa"), the usual reference is to Costa's " Corresponden/a 

 Zoologica, 1839" (page never given); the name occurs there 

 (p. 181) as applied to a freshwater bivalve, in a review of the 

 author's "Fauna Sicilia," &c., 1840 (46), to which the reader 

 is referred for details. The latter work few appear to have 

 seen ; in it thegenus and species (Galihia tenebrosa) are described 

 and apparently excellent enlarged figures given, which would lead 

 one to suppose the shell was really marine. The Marquess de 

 Monterosato, however, assures me that these figures are quite 

 fallacious, and most kindly forwarded specimens from the type 

 localitv, which is inland. These and other specimens which I 

 received from Prof. Bellini proved to be undoubted Pisidium 

 casertanum, very dwarfed and stunted, accompanied in one of the 

 gatherings by still more stunted P. personatum. 



* Misquoted by Prime in his works as " Physemoda." 



