Mr. G. B. Sowerby on a new fossil Astacus. 493 



ash-brown, upper and under tail coverts dark-brown, legs and 

 toes orange, the webs black. 



A doubt has been expressed that the occurrence of this bird 

 might not be the result of natural migration, as several had been 

 brought to this country, three or four years since : it may there- 

 fore be proper to state, that the plumage of the Duck now de- 

 scribed did not exhibit any indication that the bird had been kept 

 in confinement, and by a comparison with the plumage of the 

 adult it will be found, that this is not yet arrived at maturity, 

 probably in the second year, a circumstance very much in favour 

 of a natural migration, our rare visitors being generally young 

 birds. 



It will also be recollected that the weather for ten days pre- 

 ceding its appearance was remarkable for the severity of the 

 frost. Wild fowl were most abundant on our south and south- 

 east coasts; young birds of all three species of the genus Colymbus 

 were purchased in the London Market, and those of the genus 

 Mergus in different states of plumage ; British Ornithologists 

 are also indebted to the pages of this Journal for the record, 

 that within the last two years the Oriolus Galbula^ Anthus Rich' 

 ardi, Accentor Alpinus, GalUnula Baillonii and others, have been 

 taken in England, all of them birds extremely rare, and, compared 

 with the Duck now described, of equal extent in their western 

 migration. W.Y. 



Art. LV. Description of a new Species of Astacus found 

 in a Fossil State at Lyme Regis, in Dorsetshire, com- 

 municated hy H. T. De la Beche, £5^. F.R.S., Sfc. 

 By G. B. Sowerby, F.L.S, SfC. 



Astacus longimanus. 

 A, manibus longis, centrali cauclce segmento utrinque subserrato. 



Icon. Tab. nost. v. ii. t. xvii. fig. 1, 2. 

 A. with long hands and the Central segment of the tail slightly 

 serrated on each side. ^ 



