Miscellaneous. 



77 



previous observations on the change of tint which the infusoria that 

 colour our salt marshes undergo by age. These animalcules, which 

 are white at their birth, become green in their middle age, and do 

 not till their adult age take the purple tint which makes them so re- 

 markable. In general the green infusoria are not so often seen as 

 the red in salt marshes, which seems to indicate that these monads 

 remain but a short time in their middle state. 



We have found the same infusoria in the argilo-calcareous marls 

 which are found at Cardona beneath the rock salt. There they have 

 their beautiful purple tint, but they are in too small numbers to com- 

 municate it to the mass of marl which has remained grayish. This 

 fact also proves, that in the ancient world, as in the present one, the 

 animalcules were precipitated after their death to the bottom of the 

 waters in' which they previously lived. — Comptes Rendus, Mar. 16. 



ON THE GENUS PUPINA. BY JOHN EDW. GRAY, ESQ. 



The shell of this very curious and interesting genus has been 

 placed by different authors in very different parts of the system, 

 some persisting that it should be arranged with the marine genera 

 on account of the grooves on the left side of the mouth. From a spe- 

 cimen which Mr. Powis has very kindly given to me, I have no 

 doubt in my own mind that it is a very distinct genus of Cyclosto- 

 mid(B, for this specimen has a horny orbicular many-whorled oper- 

 culum as large as the mouth of the shell, exactly resembling the 

 opercula of some of the genera of that family. The polished surface 

 of the shell and the form of the notch is very unlike any that I have 

 hitherto observed among the shells of marine mollusca. The latter 

 is peculiar, as being funnel-shaped, wider outwards, and narrowed 

 into a slit within, and only appears as a narrow simple groove on 

 the outer surface of the peristome. 



I am acquainted with two species of this genus ; one Pupina fusca, 

 small, pale brown, with a yellowish white peristome ; and the other, 

 Pupina grandis, twice the size of the former, more ventricose, and 

 of a bright yelk yellow colour ; there is a fine specimen of the latter 

 species in the cabinet of Mr. Stainforth. I suspected that this genus 

 should be referred to the family of Cyclostomidce directly I had seen 

 the animal and operculum of Mr. Guilding's genus Megalomastoma ; 

 but from the rarity of these shells, I had little hope of so soon being 

 able to get the additional information furnished by the operculum, 

 which was alone wanted to clear up the doubt. I have lately seen 

 another shell which has the polished surface, mouth and operculum 

 of this genus, but is destitute of the groove, and must form another 

 genus of this family, for which I propose the name of Callia. — J. E. 

 Gray. 



on the byssus of unio. by john g. anthony, esq. with notes, 



by j. e. gray, esq. 

 " I have discovered another fact with regard to the Unios which 

 has escaped the notice of other collectors thus far : in one locality 

 near us (Cincinnati, U. S.)> the Unios spin a byssus. The location 



