PROF, W. K. PARKER ON AGITHOGNATHOUS BIRDS. 341 
Example 27. Chasmorhynchus nudicollis (the Naked-throated Bell-bird). 
Habitat. Brazil. Group “Tracheophone,” Miiller; family “ Cotingide.” 
It would seem as though the “ embryon atoms” of three diverse types had striven for 
mastery here : the Hemipod, the Goatsucker, and the Crow were put into the “ limbeck ;” 
the spirit that arose was the “ Bell-bird.” 
The skull of this loud-voiced caprimulgine Crow is modified from the ordinary 
coracomorphous type far more than the skeleton generally; this is often the case in 
birds. 
As far as the skull is concerned, this type has the same (but no more) right to be 
considered one of the “ Coracomorphe”’ as the Swift (Cypselus). In some respects it is 
truer to the Fissirostral type than the Swift itself; indeed, in the general texture of the 
skull, which is most exquisitely cellular and light, it comes close to Caprimulgus ; whilst 
Cypselus has a thin fibrous skull, nuch more so than its passerine relatives the Swal- 
lows. Here, then, is a point on the great Coracomorphous circle which impinges on the 
circle containing the Frog-faced Podargus, the Oil-bird (Steatornis), and the Goat- 
sucker; which latter forms the touching-point. 
Still the tracheophonous Swift goes far away from the passerines, even those nearest 
to it, the Swallows, in all the structures behind the occiput. One of the lesser of the 
true Corvide, the Jay, being of the same size as the Bell-bird, is good for comparison ; 
then let the student provide himself with the skull of a Goatsucker (Caprimulgus 
europeus) and of a Hemipod, and he will be able to follow the writer. Moreover our 
task, though asking delicate discrimination and familiarity with the bony framework of 
many birds, is yet a very easy one compared with that of tracing the atavistic germs of 
a Darwinian “ Pangenesis.” I may remark here, how smoothly the bone-surface has been 
polished and almost enamelled! the walls also being of the thinnest periosteal bone, 
and the diploé reduced to the uttermost degree of delicacy. ‘The elegant two-winged 
basitemporal region (Pl. LXII. fig. 5, G.¢) is everywhere completely welded to the sur- 
rounding parts, save in front, where the Eustachian openings (ew) are merely separated 
by a little wall of bone. Here the basitemporal lip is free; it is thick and spongy, like 
a stonecrop leaf. . 
The parasphenoid (pa.s) has spread abroad beneath the true posterior sphenoidal 
region, behind, facing most of the floor and sides of the “ anterior tympanic recess,” in 
which it is helped by the thoroughly continuous basitemporals. Like a true corvine, 
this bird has no basipterygoid processes, and the beam or rostrum runs forwards—thick, 
rounded, and solid—to the nearly perfect cranio-facial hinge. It is underfloored, all 
but its hinder part, by the palatine bones, as in Caprimulgus. The true nasal septum 
is ossified all along and directly in front of the hinge, in the middle; and in front the 
bony matter creeps down into the depth of the septum (fig. 7, s.2). Behind and below, a 
small tract of the septum is ossified (figs. 5 & 8, tr); this is the trabecular bone (belong- 
ing to the first facial arch); in front of it are two smaller bones, not united to the 
