1888.] DR. H. GADOW ON THE REMTGES OF BIRDS. 665 



Part II. 



A few Remarlcs on the Phylogenetic Develojjment of the Remiges. 



Mr. Wray has shown that the one or two rows of greater under 

 wing-coverts, Sundevall's " tectvices aversse," were originally situ- 

 ated on the dorsal side of tlie wing, like the remiges themselves, and 

 that the two hinder series of feathers gradually, during the growth of 

 the embryo, are pushed into the ventral side of the wing. This is 

 probably due to the greater development of the remiges proper, and 

 to the formation of the fascia tendinea, which connects the basal 

 portions of all the remiges with each other. 



Since this interesting discovery has been made, it is easier to un- 

 derstand the relations between the remiges and greater under wing- 

 coverts in the Ratitae and Spheniscidae, and moreover to arrive at a 

 possible explanation of the phylogenesis of the remiges from a general 

 point of view. 



Struthio possesses 20-23 cubital and 16 metacarpo-digital remiges. 

 Of the primaries, 8 are carried by the metacarpal bones, one by the 

 remnant of the third finger, 4 by the first, and 3 by the second 

 phalanx of the second finger. There is only one series or row of 

 greater under wing-coverts. 



Rhea has only 12 primaries, like certain Carinate birds. The total 

 absence of greater under wing-coverts is probably due to their de- 

 generation. 



SpheniscidfE. — Fiirbringer draws attention to the fact that in the 

 Spheniscidae there are more than 30 rows of little scale-like feathers 

 on the dorsal and on the ventral aspect of the wing, i. e. a greater 

 number of rows than there are present in any otiier bird, even all 

 the median, lesser and marginal coverts included. The largest of 

 these feathers are not, like in other birds, the most ulnar series, but 

 the last but one series on the hand, and the second and third last 

 dorsal rows of the forearm. Each of these rows contains 25-27 

 feathers on the arm, and 35-36 on the hand. Fiirbringer rightly 

 hints at two possible explanations of this exceptional condition. 

 Either that the Spheniscidae have lost all their true primaries, which 

 they possibly originally possessed, and that this row of 36 featheis 

 does not represent primaries at all ; or perhaps that only every third 

 feather represents a primary, although now degenerated, whilst the 

 other 24 feathers are modified down-feathers. However, neither of 

 these two assumptions is supported by facts. That the number of 

 feathers in one row amounts to 36, i. e. three times the number of 

 primaries of certain other Carinate birds, is most probably an acci- 

 dental coincidence ; otherwise one might assume that of every three 

 feathers of the Penguins, one had become a primary and the other 

 two had been transformed into tectrices aversae. 



I find that in a large specimen of Aptenodytes pennanti there 

 are no tectrices aversae, all the feathers of the ventral aspect of the 

 wing looking ventralwards witii their convex surfaces. This circum- 

 stance suggests the assumption that in the Penguins no rows of 



