ANATOMY OF THE SHOE-BILL. 701 



Balfenicepididte, Ciconiidae and Ibididte. But if we desire that 

 classification should represent phylogeny, we must await further 

 knowledge as to the value of the various characters which 

 anatomists have tried to use. It is no use bringing pectination 

 or powder-down patches, or a completely feathered neck into an 

 argument between Storks and Herons, if these chai'acters have 

 been independently acquired or independently lost in the case of 

 }nany diflerent groups. It is no use for systematic purposes to call 

 a particular form of syrinx Ardeine if that be a common type in 

 many different kinds of birds, or to call a doubled pectoral muscle 

 Ciconine if that be shared by many Steganopods. The fact is 

 that Steganopods, Scojnts, Balceniceps, Storks and Herons have a 

 large common heritage, consisting partly of actual common 

 structures (some of which they share with a very much larger 

 asserablage of birds) and partly of the capacity to be modified 

 in certain definite directions. The characters latent and patent 

 composing this common heritage ai'e distributed irregularly 

 amongst them, partly for reasons that we do not know and partly 

 in response to similar habits. Until the meaning and history 

 of each set of characters have been worked out very fully we have 

 less than no idea as to their real value in indicating affinitj^. 

 The only set of characters on which I have sufficient knowledge to 

 have any confidence is shown in the disposition of the alimentary 

 tract. In that respect Balcenicejys seems to me to have passed 

 through the condition common to Storks and Herons, and to 

 display specialization in the same direction as the Herons. But 

 until we have further knowledge, not so much of Balceniceps in 

 particular, but of the value of anatomical characters, the safe 

 course is to regard Balceniceps as the representative of a group of 

 equal value with Storks and Herons. 



In my opinion, however, the relation of Storks and Herons 

 to the Steganopods requires revision. Pending this, I must add 

 that John Cxould's description of Balcjeniceps as the " Grallatorial 

 t3'pe of the Pelecanidee " is at least as hap2:)y as the more confident 

 statements of later writers. 



List of References. 



1. Bartlett, a. D., On the Affinities of Balceniceps rex. P. Z. S. 



1861, p. 1.31. 



2. Beddard, F. E., Anatomy of Scopus umhretta. P. Z. S. 1884, 



p. 543. 



3. ,, Visceral Anatomy of J5«/re?w'ce^js rea;. P.Z. S. 



1888, p. 284. 



4. ,, The Structure and Classification of Birds. 



London, 1898. 



5. ,, On the Alimentary Tract of Certain Birds. 



P.Z.S. 1911, p. 47. 



6. Cazin, Maurice, L'Appareil gastrique des Oiseaux. Ann. 



Sci. Nat. iv. p. 177 (1887). 



