434 ON THE PETRELS COLLECTED DURING 



condition of the young birds, and the number, shape, and coloration of 

 the eggs points on which some stress may be laid in questions of this 

 kind are totally dissimilar in the two groups, as indeed are the habits 

 of the adult birds themselves, though no doubt both are " web-footed " 

 and more or less pelagic in habit. Such resemblances, however, can 

 hardly be seriously considered as indicating any real affinities*. 



L'Herminier, A. Milne -Ed wards, and Huxley have all, in describing 

 various points in the osteology of the Tubinares, pointed out similarities 

 of various kinds between their osseous structure and that of various 

 forms of the Steganopodes, though they still kept them close to the Laridas. 

 Eyton, on the other hand, places the various Petrels he describes 

 in the family " Pelecanidse," the Gulls forming a separate family by 

 themselves. 



But no one will be prepared, I think, to dispute that the Steganopodes 

 are allied to the Herodiones, including under that name the Storks and 

 Herons, with /Scopus, only. Thus, on osteological grounds alone, there 

 is sufficient ground for placing the Tubinares in the vicinity of the Ste- 

 ganopodes and Herodiones. And, in fact, neglecting the desmognathous 

 structure of the palate the taxonomic value of which per se is becoming 

 more and more dubious as our knowledge of the structure of birds 

 increases there is little in the characters assigned to the groups Pelar- 

 gomorphfe and Dysporomorphse by Professor Huxley (1. c. p. 461) that 

 is not applicable to the general Petrel type. 



The completely double great pectoral muscle is a characteristic only 

 found, as already observed, in the Ciconiiclse, Cathartidae, the Steganopodes 

 Zool. Chall. (except Plialacrocorax), and the Tubinares, and in all these forms it is 

 Exp. vol. iv. assoc i a ted with short colic caeca of peculiar shape (absent altogether in 

 the Cathartidse, as in some of the Tubinares), more or less completely 

 webbed feet, tufted oil-gland (except in the Cathartidaa), holorhinal 

 nostrils, a tendency of the palatine bones to unite behind the posterior 

 nares, truncated mandible, broad, strong, well-developed sternum, and 

 strongly curved, well-developed clavicles. These birds also agree together 

 in being " Altrices," the young birds being quite helpless after birth, and 

 requiring to be fed for a long time by their parents and in generally 

 laying eggs of a white, or nearly white, colour. 



The group so constituted, of which the ArdeidaB and Falconidaa must 

 also be considered as aberrant members, the first family being closely 



* No views regarding the affinities of the Petrels other than that to the Laridae 

 already discussed, and that to the Ciconiiform birds, have, so far as I know, been 

 seriously advanced by ornithological writers, Professor Garrod having abandoned his 

 early idea that the Tubinares were probably related remotely to the Anseres and their 

 allies (</. Coll. Papers, pp. 220 and 521). 



