348 VENERID^. 



shorter than they have been stated to be in ours, and 

 diverge considerably; but there is a discrepancy between 

 the accounts published by Forbes and Hanley on the 

 one hand, and by Clark on the other, as to the length 

 of the tubes, and a variation with respect to the extent 

 of their divergence is shown in the figures of Poli and 

 Deshayes. The cirri which fringe the orifices of the 

 tubes appear to be as numerous and conspicuous in the 

 one form as in the other. Many unnecessary names 

 have been bestowed on this common species and its 

 variety laminosa. I have noted ten, besides those above 

 mentioned. The V. pallida of Turton is not even a 

 variety : the outer layers have been dissolved by muriatic 

 or some other acid; and the types are " doctored" shells, 

 such as unscrupulous dealers sell to ignorant collectors. 

 All specimens have longitudinal striae. My description 

 of the teeth in ordinary examples will explain the seem- 

 ing peculiarity in the dentition of Montagu's V. laminosa, 

 as noticed by Forbes and Hanley. 



V. dysera of Born and Chemnitz (but not of Linne), 

 one of the many " ben trovato " discoveries of Laskey, 

 is West-Indian. It is the V. ting end a of Diliwyn. 

 V. granulata of Gmelin, V. Paphia of Linne (according 

 to modern authors), and V. circinata of Born ( V. Gui- 

 neetisis, Montagu) may be classed in the same category 

 of spurious species. V. subrhomboidea of Montagu is 

 apparently the adult of Petricola lithophaga, Retz, — his 

 Mya decussata (P. Ruperella, Lamarck) being certainly 

 the younger state of that shell : this species has not been 

 authenticated as British, although it is rather common 

 in the Mediterranean and the west of France; Mr.J.D. 

 Humphreys's collection of Irish shells contains a spe- 

 cimen found by him in Cork Harbour, but I have reason 

 to suspect that it came from a piece of ballast stone. 



