146 DIGESTIVE SYSTEM 



respect the Pygopodes. These {Colymhidx and Podicipedidx) shew 

 unmistakable affinities AAdth what may be called generalized or low 

 Gralline forms ; their four or five loops are closed, orthocoelous, and 

 alternating. The Pygopodes connect the large assemblage of the 

 Waders with the following congregation, of which the Herodii, 

 Steganopodes, Tubinares, and Spheniscidx are all divergent types. A 

 very close connexion exists between the Herodii and the Steganopodes, 

 and this is supported by numerous other characters. The Tubinares 

 are in more than one respect the most specialized outcome of this 

 great collective Order, and reach in the typically mesogyrous 

 Procellariinse their highest development. 



The Spheniscidx are very specialized. They possess undeniable 

 characters in common with the Pygopodes, Steganopodes, and Tubinares ; 

 they are on the whole orthocoelous, but the extreme length of their 

 gut thrown into numerous straight and oblique, or quite irregular, 

 convolutions renders comparison very difficult. 



The Anseres, to which belongs Palamedea as a probably very old 

 member, are all orthocoelous and combine peri- and plagioccelous 

 characters in their second loop. The five or six principal loops are 

 alternating ; the last four are closed and straight. As typically 

 orthocoelous, aquatic birds, and as Prsecoces they agree with the 

 Pygopodes, and the root of the stock of the Anseres has to be looked 

 for in this direction alone. 



The Pelargi, containing the Hemiglottides {Ibis and Platalea), 

 Phcenicopterus, and the Ciconim, are rather diverging forms, which can 

 be characterized as possessing four very long and mostly closed loops 

 (with occasional secondary loops intercalated), of which the first three 

 have a tendency to coil their apical ends into more or less irregular 

 spirals : this leads sometimes to an almost mesogyrous formation. 



The Hemiglottides approach nearest to the Limicolsc, although 

 their points of resemblance with Ntimeniiis may possibly be cases of 

 convergence only. Very closely allied to, in fact inseparable from 

 the Hemiglottides, and connecting them with Tantalus, and thus with 

 the Ciconide proper, is Phcenicopterus ; there is not one single feature 

 in the whole of the Digestive System in which this bird difters from 

 the Pelargi or resembles the Anseres except in the presence of small 

 but functional c^ca, which are nearly lost in the Pelargi. But 

 these caeca stand in direct relation to the food of the Flamingoes, 

 which consists of the confervae in the mud of the lagoons. The 

 zoophagous Pelargi have lost them, the phytophagous Flamingoes 

 have preserved them. 



The Ciconiinse proper, represented by Ciconia, and connected with 

 the former genera by Tantalus, are essentially telogyrous ; their second 

 loop is right-handed, and accompanies the duodenum ; this is a rare 

 feature, and is of taxonomic value for the diagnosis of the subfamilies 

 of the. Pelargi. 



