4 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



tlo, ronccrniiig the position or rank of certain forms, it of course 

 becomes necessary to consider carefully the points of disagreement, to 

 weinh impartially the evidence and arouments adduced by the advocates 

 of such divcro-ont decisions, and, if possible, decide independently as 

 to the seemino-ly better allocation of the form in question. This has 

 been attempted in the following scheme, but the author is fully con- 

 scious that his disposition of such doubtful cases may still not be tinal, 

 especially wiien ditlerent from previous decisions, as in a few cases 

 has been the result of his revision. 



It is unfortunate that those who possess the most thorough knowl- 

 edge of avian anatoni}' and morphology do not always seem to have 

 succeeded in satisfactorily diagnosing the groups which they adopt, 

 nor in clearly presenting* a synthetic sunnnary of the facts revealed 

 through their investigations. So-called diagnoses are sometimes 

 found, when carefully analyzed, to be really not diagnostic at all; 

 more often thev prove to be so in part only. A b}" no means extreme 

 example, the case of the Limicolse and Lari (suborders of the Order 

 Charadriiformes), as defined in Gadow's Classification of Vertebrata 

 (1898, p. 35), may be given for illustration. These two groups are 

 thus characterized by Dr. Gadow: 



LiMicoL^. — "Nidifugous, schizognathous. without spina interna 

 sterni; hypotarsus complicated."' 



Lari. — ""Aquatic, schizognathous, vomer complete. Without basip- 

 terygoid processes. Front toes webbed; hallux small or absent. Large 

 supraorbital glands." 



Of the characters mentioned in these two diagnoses the following are 

 common to the two groups, and therefore are not diagnostic of either: 

 (1) Nidifugous young;' (2) schizognathism; (3) complete vomer; 

 (4) absence of spina interna sterni; (5) absence of basipterygoid proc- 

 esses;- (6) webbing of front toes;^ (7) small or obsolete hallux; 

 (8) aquatic habits.* 



The differential characters of the tw^o groups are thus reduced to 

 the following: 



LiMicoLiE. — H3^potarsus complicated; supraorbital glands small. 



Lari.— Hypotarsus simple; supraorbital glands large. 



With this example of so-called Suborders which are characterized 

 by a very small numl)er of relatively unimportant differences may ))e 

 contrasted that of the several subdivisions of the Order Gruiformes, 

 to which Dr. Gadow only allows family rank, although apparently far 

 better characterized than the so-called suborders of Charadriiformes, 



' The young of the Lari are not, it is true, strictly nidifugous, but they are often 

 more nearly so than nidicolous. ' 



■'Basipterygoid jirocesses are present in some LimiroLr, absent in others. 

 ■'The front toes are webbed in sonie Limicohie (e. g., Ilhiaudopus). 

 *Tlie Phalaropes are quite as truly aquatic as Gulls. 



