. TETRAGONOEBS. 551 
duller bird, inasmuch as it lacks the shining black long nuchal crest shown in the 
original figure of the type and in all dissected male birds. 
This difference in the sexes is also shown in Tetragonops rhamphastinus, but is not 
noticed by Captain Shelley in his catalogue; and though mentioned in Marshall’s 
monograph in the case of 7’. frantzii is not alluded to in the case of the allied form. 
All the specimens of this bird we have seen came from Costa Rica, except one, and 
this was sent by Arcé from Veraguas after the second paper on his birds was published 
in 1870. 
Fam. RHAMPHASTIDZ, 
The Family Rhamphastide is restricted to the Neotropical region, and is found 
almost universally over the heavily forested districts from Southern Mexico to the 
confines of Argentina, some forms being restricted to the upland woods of the higher 
mountains, others to the vast forests of the lowlands. 
Of the five genera into which the family is divided, four occur within our limits, 
Andigena alone being absent. Fhamphastos is represented by three species out of a 
total of fourteen, Pteroglossus by three out of eighteen, Selenidera by one out of seven, 
and Aulacorhamphus by three out of fourteen. We thus have ten species out of a 
total of fifty-nine known forms, and our region is fairly stocked with members of this 
singular family; but far larger numbers are found in South America, the metropolis 
of the Rhamphastide being the upper waters of the great Amazons basin and the 
eastern slopes of the Andes from Colombia to Bolivia. 
The enormous size of the bill in the Rhamphastide at once renders these birds 
easily recognizable. This organ is of curious structure, very light, but strongly built 
within by a bony network. ‘The tongue is also very peculiar, being long, narrow, and 
thin, and deeply lacerated towards the end. ‘The tail-feathers, as in the Capitonide, 
- are ten in number, the oil-gland is tufted, and there are no ceca. The Rhamphastide 
further differ from the Capitonidee in the form of the vomer, which, instead of being 
bifurcated at its distal end, is truncated and has a rounded extremity. 
In the general structure of the body the Toucans closely resemble the Capitos and 
Woodpeckers—so much so, that, apart from the cranial characters, slight grounds of 
separation exist, a point strongly insisted upon by Garrod and Forbes. 
The Rhamphastide attracted Gould’s attention early in his career, and he produced 
two large illustrated monographs of the family. A small edition, also illustrated, was 
brought out by J. H.C. F. and J. W. Sturm in 1841, and the ‘Catalogue of Birds 
in the British Museum,’ vol. xix., contains a complete synopsis of the family by 
Mr. P. L. Sclater. The latter book contains lists of all the specimens gathered 
by us for this work, aud has been of great use to us in our account of the species 
here treated of. 
