270 phockkdincs ()1<' thk malacdlogical society. 



2. Grateloupia. 



This name was given by Desmoiilins to certain shells of Miocene 

 age which occur near Eordeaux in France, in Italy, and in Austria, 

 but only two species have been described. The typical form is tbe 

 Donax irregularis of Basterot (1825), which was more completely 

 described and well figured bj- Desmoulins in 1828 ^ as tlie type of a new 

 genus, to which he gave tlie Tiame of Grateloupia. The following is that 

 part of his description which relates to the hinge : " Dentes cardinales 

 primarii (ut in Ci/therea) divaricati, tres in utraque A-alva ; quibus 

 accedunt in valvis ambabus dentes cardini-seriales 3-6 lamellosi, 

 paralleli, ad natem convergentes oblique rugosi, margineque denticu- 

 lati, sub ligamento ad latus testae posticum instructi. Dens lateralis 

 nnicas, anticus, sub ano (ut in Cijlhtrca) in valvu sinistra positus ; 

 fovea in valva dextra alterius valvae dentem lateralem recipiente." 



From tins account (which is given also in Frencli) it is quite clear 

 that Desmoulins thoroughly understood the structure of tbe hinge, 

 for he rightly credits it with three principal or primary teeth and 

 several parallel accessory te(!th, pUiced obliquely under the ligament, 

 whicli he terms ' cardini-seriales ', not cardinales. 



It is curious that although he was fully aware of the existence of 

 a similar sliell in the Miocene deposits of Bordeaux, namely the 

 Donax difficilis of Basterot, yet he and Deshayes regarded this as 

 belonging to Cythcrea. Possibly this may have been due to his not 

 possessing sufficiently good specimens, for the dentition is really tlie 

 same, though the number of accessory ridges or teeth is less — only 

 two or tliree in a more contracted space. It was, however, recognized 

 as a Grateloupia by C. !Mayer in 1858.- 



Deshayes accepted the genus in 1848 {Traite EUmenlaire de 

 ConcJn/liolociie), but S. P. Woodward considered it to be only of 

 subgeneiic rank ; in the first edition of his Ulanual (1851) he placed 

 it as a sub-genus of Cytherea, and in subsequent editions as a sub-genus 

 of Triyona, which is the l^irela of Link. Most subsequent authors, 

 d'Orbigny (1852), Sowerby (1852), Bronn (1854), Pictet (1855), and 

 Hoernes (1862), accepted it as a genus ; while Fischer, in his Manuel 

 de Coiichylioloyie of 1 887, not only described it as a genus, but separated 

 it entirely from Tivela, which he placed as a sub-genus of Meretrix. 



It seems to liave been Fischer who first imagined that a posterior 

 lateral tootli existed in tlie riglit valve of Grateloupia. He correctly 

 stateil that there are " trois dents cardinales divergentes" in each 

 valve, and "plusieurs plis dentiformes, paralleles, places en arriere de 

 la dent cardinale ])osterieure ", but he adds that there are two anterior 

 lateral teeth and one posterior lateral in the right valve. jSTo doubt 

 this was the chief reason why he separated Grateloupia from Tivela. 



His opinion has naturally influenced other French writers, and 

 it has recently been adopted by Messrs. Cossmann & Peyrot,^ who 



^ Actes Soc. Lin. Bordeaux, ii, p. 243, pi. vi, ligs. 1-5. 

 - Journ. de Conch., tom. vii, p. 88, 1858. 



^ "Conch. Neogen de I'Aquitaine " : Actes de la Soc. Linn., Bordeaux 

 tom. Ixiii, 1909. 



