118 Letters, Annoimcements, S^c. 



10 Chandos Street, 



Cavendisla Square, 



December 3, 1884. 



Sirs, — Though we have not had an opportunity of com- 

 paring the types^ we have little doubt that the Phompara 

 described from Roraima, in the last volume of ' The Ibis ' 

 (1884j J). 445), as P. plueoptlla is the same as Phompara 

 fumosa, Lawrence, from Trinidad (Ann. Lye. N. Y. x. p. 396, 

 1874). Both birds are described as being of a uniform 

 fuHgiuous black above, unreHeved by olive-green on the back, 

 as in the allied species P. bicolor &c. 



We are, yours &c., 



O. Salvin and F, D, Godman. 



lingular Development of Opisthocomus. — Mr. Coale, of 

 Chicago, sends us an account of an apparently very remark- 

 able discovery in the development of the Hoatzin [Opistho- 

 comus cristatus) made by Mr. Edward M. Brigham. The 

 exact facts are not very clearly stated in the paper (which was 

 read before the Chicago Academy of Sciences on October 

 14th, 1884), but the following passage seems to contain the 

 pith of the discovery : — 



" While making embryological studies in the interior of 

 the great island of Marajo, on the small river Anabiju, I dis- 

 covered the quadruped-bird. 



''After having examined many specimens of various ages, 

 I found that from what corresponds to about the embryonic 

 state of development of the common fowl at the tenth day 

 of incubation^ the fore feet showed their characters unmis- 

 takably throughout their egg-development, and to a period 

 of several days after hatching the fore feet, toes, and claws 

 held their characters as such, as unmistakably as those parts 

 of the posterior members. 



" Later a progressive modification manifested itself by re- 

 ducing the digits, exfoliating the claws, and developing these 

 anterior members into those characteristic of a bird. There 

 is, among the higher vertebrate animals, so far as I know, no 



