Jeffries on the Fi>igers of Birds. 7 



but natural to compare it part for part with the limbs of these 

 animals. 



If we take an adult bird we find two ossicles at the distal end 

 of the forearm ; these are called the ulno-carpal and radio-carpal 

 bones. Next we have a compound bone made up of shafts, rep- 

 resenting as many metacarpals. These in turn are capped by 

 finger points, of the formulas i, 2, 1, (e.g., Passeres), 2, 3, 1 

 (e. g., Ducks), or 2. 2, 1 (e. g., Coot). 



The two carpel bones have, as a rule, been simply referred to 

 the first row ; while those of the second were considered to be 

 anchvlos with the metacarpals. Whether the metacarpals are 

 the I— III or the II-IV has been a mooted question, Rolleston, 

 Huxley- and Gegenbaur holding the first view and Owen, Wy- 

 man, Morse, and Coues holding the second view. 



The first study of the development of the carpus was made by 

 Gegenbaur, who showed that the carpals were joined to the 

 metacarpals, and that the three metacarpals were at first separate. 

 Next Dr. Morse studied the carpus and tarsus of small birds in 

 their normal condition. Bv this means he demonstrated the ex- 

 istence in the embryo of the radiale, ulnare, and 2d, 3d, and 4th 

 carpals of his determination, also in some cases the intermedium 

 ( Dendrceca cestiva), and the centrale ( Tyrannus carolinensis) . 



About the same time Rosenberg studied the carpus of the chick 

 in a systematic way, longitudinal and -transverse sections being 

 made of the wing in various stages of development. The result 

 is that he has shown that the carpus is represented by the radiale, 

 intermedio-ulnare, and two carpal bones supposed to be the ist- 

 2nd and 3rd— 4th. Also that the metacarpus is represented bv 

 four long bones, the fourth one being on the ulnal side. These 

 he considers to be the first four.* 



Very good sections can be obtained by soaking the wing in a 

 2 %S c /o solution of chromic acid and then in alcohol of increasing 

 density till 95 r / c is reached. The wing thus treated should be 

 imbedded in paraffine or some similar substance, then cut in the' 

 thinnest possible sections and mounted in balsam or a glycerine 

 compound. It is not necessary to stain the object, though this is 

 an advantage. A wing can be made perfectly transparent for 



* I, however, find what seems to be a discrete 1st carpal in the Redstart; Morse has 

 done the same of other birds. 



