88 SAXICAVID.E. 



specimens the laminar ridges are fringed and resemble 

 those of the lovely Venus lamellata. We learn from the 

 interesting experiments made by M. Beudant, as to the 

 capability of marine mollusks living in fresh water, that 

 out of 20 individuals of V. Irus 16 remained alive at the 

 end of 22 days after the sea-water in which they were 

 placed had been gradually mixed with fresh, so as to 

 render the proportions equal, and that all the survivors 

 were instantly killed on being immersed in quite fresh 

 water. Of Mytilus edulis 30 individuals lived for 5 

 months in the admixture, and for 15 days in fresh 

 water. 



Its specific name may have been derived from the 

 ragged look of the shell, compared with that of its 

 original congeners, the Donaces. Irus was a common 

 beggar and messenger at Ithaca, who insulted Ulysses 

 in his own palace upon his return home incognito, and 

 was knocked down by him with a blow of his fist. 

 Among the Roman poets the name symbolized wretched 

 poverty and that reverse of fortune which Ovid expressed 

 in the following line, 



" Irus et est subito, qui modo Croesus erat." 



This characteristic shell is the Tellina Cornubiensis of 

 Pennant, Cuneus foliatus of Da Costa, Venus cancellata 

 of Olivi (but not of Linne), and Venus Bottarii of 

 Renier. 



I have a specimen of Venerupis Lajonkairii, Payrau- 

 deau (V. decussata, Philippi), which came from the col- 

 lection of Mr. George Humphreys, with the undermen- 

 tioned name and note of its locality, " Venus striata, H. 

 Brighthelmstone W. H. 1768." It is a native of the 

 Mediterranean, and resembles the young of Tapes de- 

 cussatus ; but, besides the difference of hinge-structure, 



