408 PURPLE MARTIN. 



inch 1 twelfth wide, the remaining part oblong, obtuse, 3 twelfths 

 wide. Cloaca globular, 9 twelfths in diameter. 



Trachea 2^ inches long, considerably flattened, of the uniform 

 breadth of 2 twelfths, excepting at the lower part, where it contracts 

 to 1^ twelfth. The rings are extremely feeble, about 60, with two 

 terminal dimidiate rings. Bronchi moderate, of about 15 half rings. 

 The muscles as in the other species. 



If the use of the elongated bristles at the base and sides of the 

 bill be to enable the Goatsuckers the more easily to secure their prey, 

 as it very probably is, why is the Night Hawk destitute of them, and 

 what are the circumstances in its economy that render them unneces- 

 sary ? 



PURPLE MARTIN. 



HiRUNDO PURPUREA, LiNN. 

 PLATE XXII. Vol. I. p. 115. 



Although this beautiful Swallow reaches the vicinity of the Arctic 

 circle earlier than others, it is said to migrate far within the tropics, 

 as, according to Mr Swainson, it was " observed in numbers around 

 Pernambuco, eight degrees and a half south of the line." Dr Town- 

 send found it on the Rocky Mountains, and I met with it breeding in 

 the Texas in April 1837. Although it has not been mentioned whe- 

 ther it breeds at Pernambuco, it is probable that it does, for in the 

 United States it nestles in favourable situations from their southern ex- 

 tremity to their northern limits, selecting fissures of rocks and hollow 

 trees in the wilder or less inhabited parts. I saw none, however, in 

 Labrador or Newfoundland. The following notice by Thomas M. 

 Brewer, Esq. of Boston, I present to you with pleasure. 



" A trivial fact will I think shew how exceedingly attached these 

 birds are to certain districts. Not many years ago, an unusually cold 

 season destroyed all the birds of this species in the immediate neigh- 

 bourhood of Boston ; and, although those met within twenty miles of 



