1889. ] CONVOLUTIONS IN BIRDS. 313 
There remain, lastly, some unexpected resemblances between the 
Pelargi and the Diurnal Birds of Prey; the chief connection is formed 
by the telogyrous character, the mode in which additional loops of 
the lengthened gut are stowed away, and the tendency to convert 
some or one of the principal loops into regular spirals. Amongst 
the Accipitres, the Old-World Vultures especially exhibit striking 
Ciconiine similarities. As regards the Cathartide, I have to deplore 
want of material. One badly preserved specimen of Cathartes 
atratus differed greatly from the Accipitres in several particulars ; 
one of the points being the widely open and periccelous second loop, 
a feature occasionally met with in the Hemiglottides. 
Whatever may be the value of these resemblances between the 
Pelargi and Raptores, they are the only points by which the Raptores 
can be connected with the rest of the Carinate; therefore the view 
of Garrod to let both form part of his order Ciconiiformes, which 
is adopted by such an authority as Fuerbringer, becomes strengthened. 
It is advisable to treat the Cathartidee and Accipitres (7. e. the rest 
of the Raptores diurni, Serpentarius not having been examined) as 
equivalent groups, and to combine them under the one name Rap- 
tores. 
The Psittact are distinctly telogyrous; all their five principal 
loops are closed and alternating ; this, with the presence of a crop, 
and the absence of functional cxeca, are features which occur again 
together only in the Accipitres. The absolutely vegetable food of 
the Parrots would sufficiently account for the differences which exist 
between them and the entirely zoophagous Accipitres. However, 
this indication of a possible relationship between the Birds of Prey 
and Parrots is as little binding or satisfactory as other suggestions 
based upon other organic systems. Parrots are Psittaci, and semi- 
psittacine forms, either recent or extinct, are unknown. 
All the remaining Birds, viz. Garrod’s Piciformes, Passeriformes, 
and Cypseliformes (with the addition of the Striges, Musophagide, 
and Cuculidz, and after the exclusion of the Psittaci), have collec- 
tively been called Coracornithes by Fuerbringer. This I consider a 
great step in advance. They represent together the higher birds in 
opposition to those of lower organization, which, from a very broad 
point of view, can be divided into two equivalent sets : 1, those chiefly 
terrestrial (all the Plagio- and Periccelous birds, corresponding 
roughly with Fuerbringer’s Alectorornithes+ Charadriornithes) ; and 
2, those chiefly aquatic (all the typically orthoccelous birds=Fuer- 
bringer’s Pelargornithes). It is of course self-evident that such a 
division of the Aves into three great sets can be maintained only on 
the broadest phylogenetic basis, taking into account solely the fact 
that their organization gravitates towards three centres. Naturally, 
there can be nothing surprising in it that birds, which from all their 
principal points of organization point to one centre, have, owing to 
change of habits, secondarily assumed characters which are primitive 
in, and typical of, another centre. Examples of such convergence are 
the Laride, Accipitres, Pelargi, Striges, and possibly the Psittaci. 
Concerning the ‘ Coracornithes,” it would be very difficult to 
