276 JOURNAL OF CONCHOLOGY, VOL. II, NO. 9, JANITARY, I906. 



Bucquoy, Dautzenberg, and DoUfus have, however, described a 

 Mediterannean variety, which has the shape of fusca combined with 

 the colouration of the type, and for this they proposed the name 

 ifiter/nedta} 



Tapes aureus (Gmelin) is the next species to claim attention. It 

 was based on the figure of an English specimen given by Lister 

 (p. 404, fig. 249), and therefore there can be no doubt about the type, 

 which is the form prevalent in the North Sea and the English Channel. 

 It is a solid, triangularly-oval shell, generally inflated, with prominent 

 umbones, sculptured by strong concentric grooves, which are crossed 

 by obscure and irregular radiating lines. The lunule is defined by an 

 impressed line. The inside is white with a tinge of golden-yellow in 

 in the umbonal part of the shell. The muscular impressions are fairly 

 large, and the pallial sinus varies in size but is generally small. 



In the typical form, the ventral margin is strongly arcuate, and 

 sometimes sinuous or irregularly curved ; from this Jeffreys distin- 

 guished a more regularly oval form by the varietal name of ovata ; and 

 a rhomboid compressed form which he called quadrata. In 1893, the 

 authors of " Les Mollusques Marins du Rousillon " described a 

 rugose variety from the Bosphorus under the name of rugata {op. cit., 

 vol. 2, p. 426, pi. 63, fig. 7). 



Now, let us turn to the Mediterranean forms out of which a number 

 of so-called species have been manufactured, Lamarck being respon- 

 sible for five at least, and many others having been added by 

 M. Locard. It is not necessary to discuss or even to enumerate all 

 these, since they were all reviewed and grouped by the French 

 conchologists, Messrs. Bucquoy, Dautzenberg, and DoUfus, in their 

 excellent memoir on the Marine Molluscs of Rousillon (vol 2, p. 414, 

 et seq.). It seems best, therefore, to give first a resumd of the opinions 

 held by these authors in 1893, and at the same time to indicate how 

 far they have since been modified, according to information for which 

 I am indebted to M. Dautzenberg. Afterwards I will state my own 

 views on the subject of the specific value of their groups. 



In the work above mentioned all the cognate forms are grouped 

 under the specific name of Tapes aureus, and the authors describe 

 this as a polymorphic species, among the various forms of which they 

 distinguish "five principal varieties round each of which numer- 

 ous variations of secondary importance may be grouped." In point 

 of fact they recognise one specific type and four sub-species, though 

 they do not use these terms of nomenclature. Their five principal 

 varieties are : — 



1 " Les Mollusques Mai-ins du Roussillon," vol. 2, p. 436, pi. 65, fig. 5, 1893. 



