658 CYGNUS IMMUTABILIS. 



severe weather of January, 1838, several flocks of these Polish 

 Swans were seen pursuing a southern course along the line of 

 our north-east coast, from Scotland to the mouth of the 

 Thames, and several specimens were obtained. The circum- 

 stance of these flocks being seen, without any observable dif- 

 ference in the specimens obtaiued, all of which were distinct 

 from our Mute Swan ; the fact also, that the Cygnets, as far 

 as observed, were of a pure white colour, like the parent birds, 

 and did not assume, at any age, the grey colour borne for the 

 greater part of the first two years by the young of the other 

 species of Swans ; and an anatomical distinction in the form 

 of the cranium, which was described by Mr. Pelerin in the 

 Magazine of Natural History, induced me to consider this 

 Swan entitled to rank as a distinct species, and, in reference 

 to the unchangeable colour of the plumage, I proposed for it 

 the name of Cygnus immutabilis." 



