1889.] | MR. P. L. SCLATER ON OPISTHOCOMUS CRISTATUS. 57 
February 19, 1889. 
Dr. St. George Mivart, F.R.S., Vice-President, in the Chair. 
Mr. Sclater exhibited a series of specimens of the eggs and chicks 
of the Hoatzin (Opisthocomus cristatus), obtained by Mr. J. J. 
Quelch, of the Museum, Georgetown, Demerara, on the Canjé Creek, 
Berbice River, in 1888, and made the following remarks :— 
In 1884 Mr. E. M. Brigham, in a paper read before the Chicago 
Academy of Sciences (see ‘ Ibis,’ 1885, p. 118), made some extraor- 
dinary statements about the condition of the wings in the embryo of 
the Hoatzin (Opisthocomus cristatus), as observed by him while 
making “ Embryological Studies”’ in the island of Marajo, on the 
Lower Amazons. 
Mr. Brigham stated that during the latter portion of the period of 
incubation, and for several days after hatching, the fore feet, toes, 
and claws of this bird had the appearance of feet, and afterwards 
evolved into wings ; he consequently called the Opisthocomus a 
* quadruped bird.”’ 
When my son went to British Guiana in 1886 I called his special 
attention to this subject, and requested him to get me specimens of 
the eggs and young birds of Opisthocomus for examination. Want 
of time prevented him from effecting this (see ‘ Ibis,’ 1887, p. 319) ; 
and I consequently applied to Mr. Quelch, the curator of the George- 
town Museum, to aid me in this matter, and obtained for him from 
the Royal Society’s Donation Fund the sum of £5, to enable him to 
undertake the necessary expedition. 
Mr. Quelch most kindly acceded to my request, and made two ex- 
peditions to the Canjé Creek of the Berbice River, in 1888, for the 
purpose. When he first went there, in March last year, he found 
the birds abundant, but only just beginning to lay (see ‘ Ibis,’ 1888, 
p. 378). Mr. Quelch consequently made a second expedition, and 
writing from the Berbice Hotel on May 24th of that year, announced 
that he had made a pretty complete collection, consisting of twelve 
adult birds, a dozen or more of nestlings of different ages, besides 
chicks and eggs. ‘This series of specimens reached me safely last 
autumn, and has been placed in the hands of our Prosector, Mr. F. 
E. Beddard, for examination. Mr. Beddard is now preparing a paper 
for ‘The Ibis’ on this interesting subject. In the meanwhile I 
exhibit some of Mr. Quelch’s specimens of the young and eggs. 
The young, it will be observed, are peculiar for having the fore 
limbs well developed and the claws on the pollex and index both 
present and of large size. According to a paper by Dr. C. G. 
Young, recently published in the ‘ Notes from the Leyden Museum’ 
(vol. x. July 1888, p. 169, pl. 8), they would seem to use these 
claws for the purpose of leaving the nest when young and climbing 
about the branches of the trees. ‘There is thus some foundation for 
Mr. Brigham’s story of the “ quadruped bird.” 
