630 BR. p. CHALMERS MITOHELIi ON THE [DeC. 17, 



has placed material (some of it belonging to the Society, and some of 

 it his own) at my disposal. I have actually dissected the following 

 forms : -- 



Eallidae .... Aramides myennensw. 

 „ ypecaha. 

 Fulica leucoptera. 

 Gallinula cMorojtus. 



„ phoenicurus. 

 tfypotrenidia philippensis. 

 Porzana Carolina ^ 

 Rallus celehensis. 

 ,, longirostris. 

 „ maculatus. 

 Cxruidas .... Balearica chrysopelargus (Gruinae). 

 Aramus scolopaceus (Araminas). 

 Psophia leucoptera (Psophiinse). 

 „ ohscura (id.). 

 'Dicholophidge. Cariama cristata. 

 Otididse .... Otis tarda. 

 Ehinochetidae. Rhinochetus juhatus. 

 Eurypygidae . . Eurypyga Jielias. 

 Heliornithidae. Heliomis fulica (sen Podoa surinamensis). 



I have, moreover, made full use of the published observations 

 of Beddard (1), Gadow (4), and Fiirbringer (3) on these and 

 allied forms, but any detailed statements which I make in this 

 paper I have myself observed or verified unless I cite them on the 

 authority of their author. 



The direct object of the enquiry the results of which are now to 

 be set out, was a prosecution of investigations to which my 

 discovery of the eutaxy in the wing of certain Pigeons (8) led me. 

 I came to the conclusion that in the Columbidae the diastataxic 

 condition of the wing was primitive, and that the eutaxic condition 

 was derived therefrom by a secoudary closing up of the diastema 

 in the ranks of feathers. I found that there was a general 

 coincidence between the specialized condition of the wing and 

 specialized conditions of other anatomical structures, and a similar 

 general coincidence between the primitive condition of the wing 

 and less specialized conditions of other anatomical structures. 

 Later on I studied the structure of Kingfishers, a group in which 

 the occurrence of both conditions of the wing was known, and I 

 was able to show (9) that also in that group there existed a 

 correlation between specialization of the wing and specialization of 

 other anatomical structures. In a later memoir (10) dealing with 

 the modifications presented by the Alimentary Canal in the whole 

 group of birds, I had occasion to employ a precise terminology for 



^ Beddard (1) states that P. Carolina is exceptional in Laving a nude oil- 

 gland ; in the specimen I examined the gland was definitely tufted, and the 

 same was true of some chicks that I examined along with Mr. Pycraft at 

 the" British Museum. 



