Occasional Notes. 179 
no external sexual characters, ., other than those of 
plumage, the young males cannot be distinguished from 
the females. In all these birds, a greyish or brownish 
slate colour predominates under these conditions, and 
the differences between the two sexes become apparent 
by the development of spots of colour on the feathers of 
the young males initiating the final blaze of plumage of 
the adult birds. From the dull slate colour, the pompa- 
dour cotinga passes to its gorgeous purple body, with 
white wings : the purple-breasted cotinga to its deep 
blue body with purple breast; and the purple-throated 
cotinga to its lovely pale-blue body with the purple 
brooch upon its throat. 
Numerous other instances such as the scarlet ibis, the 
cock-of-the-rock, etc., might be mentioned ; but the 
above will serve to dire6t attention to this remarkable 
condition in nature, where the primal inconspicuous 
covering of birds has, in the male sex, been gradually ex- 
changed for a brilliant and conspicuous garment, the 
better to fit them as centres of attraction for their dowdy 
mates. 
Fossilized Conch Shells.* — These fragments of fos- 
silized shells (Strombus gigasj, were found strewn about 
* The fossils here referred to consist of some interesting fragments 
presented to the Museum by Mr. Nind, and exhibited with an ordinary 
so-called shell-chisel, lent by him. The chisel is evidently man's work ; 
and the fossil fragments appear to be the rough material from which 
the finished chisels were prepared. It seems almost certain that the 
thick parts of the fossil shells were used for this purpose. References 
bearing directly on this point will be found on pp. 737 and 739, Smith- 
sonian Report, 1884, in a most valuable and interesting paper by Mr. 
Otis T. Mason on the Guesde collection of antiquities made at Point- 
k-Pitre, Guadeloupe.— J. J. Q. 
Z 2 
