56 



Var. y. Totą crocea : long. '2i, lat. 1; poli. 



Hud. ad Montem Christi. 



The spire of įhis is somevvhat more developed than that of the 

 shells above described ; and elevated transverse lines surround most 

 of the specimens. In some, traces of atterapts at the longitudinal 

 lineations are found. After a careful examination, I cannot sepa- 

 rate this variety specifically from the other two. The elevated 

 transverse lines are to be found in both the others. 



Found in sandy mud in the clefts of rocks.^-W. J. B. 



In further illustration of his Paper " On the Laws that regulate 

 the Changes of Plumage in Birds," Mr. Yarrell exhibited stveral 

 varietiesof British species, nhich possessed in partonly the plumage 

 common to the race. In some of these the feathers assumed at the 

 moult were of the natūrai colour, and distinctfrom those previously 

 borne ; from vvhich it was inferred, that, as the bird increased in 

 age and strength, the plumage 'vould assume entirely the colours 

 peculiar to the species. 



Mr. Yarrell also referred to sonae newly-collected series of 

 feathers, which were shown. They were taken from birds at this 

 time assuming the plumage of summer. In the black-tailed Godvoit, 

 Liniosa melanura, Leisi., many of the old feathers produced at the 

 preceding autumn moult still retained the colours they had borne 

 through the winter ; others were changing ; and some had entirely 

 assumed the colours peculiar to the breeding season, bearing the 

 šame tints and markings as some nevv feathers, the webs of vvhich 

 were only partly exposed. A series of feathers from the breast of 

 the Golden Plover, Charadrius pluviulis, Linn., were also sho^vn, — 

 some entirely vvhite, the colour peculiar to winter j some entirely 

 black, being the prevailing colour of the breeding season ; and 

 others bearing almost every possible proportion of well-defined 

 black and white on the šame feathers. 



Severai feathers were also shown nhich \vere taken from a Her- 

 ring Guli, Larus argentatus, Brunn., in its third year, vvhich is now 

 at the Society's Gardens. This bird was examined at Christmas 

 lašt. Severai tertial feathers vvere found to have their basai half 

 blue-grey, the other half mottled with brovvn. Twp notches were 

 made with scissors in the webs of these feathers, intended to refer 

 to the tno colours then present. Some other feathers were wholly 

 mottled with brown, and \vere marked with one notch. This bird 

 was re-examined in April. The tertial feathers, vvhich, vvhen 

 marked, vvere of two colours, vvere now entirely blue-gre)'; one 

 feather vvas tipped with vvhite. The other feathers, vvhich, vvhen 

 marked, vvere vvhoUy mottled, vvere novv, for two thirds of their 

 length, pure vtrhite, the terminai third alone retaining the mottled 

 brovvn. 



