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 Cathartidse, 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 Carinatse ; 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 (i. 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 Psittaci are distinctly telogyrous ; all their five principal 

 loops are closed and alternating ; this, with the presence of a crop, 

 and the absence of functional caeca, 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 zoopliagous 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, Musophagidse, 

 and Cuculidffi, 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 orthocoelous 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 Laridse, Accipitres, Pelargi, Striges, and possibly the Psittaci. 



Concerning the " Coracornithes," it would be very difficult to 



