2-J2 SOME RESULTS OF OSTRICH INVESTIGATIONS. 



Second and Third Rok<s. — While the great majority of 

 ostriches have only the single incomplete row of uncler-coverts, 

 birds are occasionally found which bear feathers belonging to a 

 second and even to a third row of under-coverts. They are much 

 more likely to occur on southern birds than on northern. In one 

 Cape cock, as many as 13 alternating smaller plumes were present 

 next to the first row of under-coverts. and in front of these were 

 four others alternating with them, and manifestly members of a 

 third row. They tended to give to the wing the appearance of a 

 covered under-surface, altogether different from the generally 

 naked effect. Not unfrequently detached feathers of the second 

 and third rows are present at any part of the row, or several may 

 occur in regular succession, the middle members of the row being 

 more likely to a])pear than those towards the end. Only in one 

 farmer's birds, however, have the nearly complete second and 

 third rows been found, but as they appear in the progeny also, they 

 are deemed to be germinal in their origin. The additional feathers 

 are nearly always fully formed, and, like the first three rows of 

 upper-coverts, they are successively smaller from the first to the 

 third row. Occasionally, however, vestigial imperfect feathers 

 occur, as if the individual plumes were going through a gradual 

 process of degeneration. 



The only feasible explanation which can be advanced for the 

 rare presence of second and third row under-coverts is that the 

 ancestors of the ostrich were, like modern flying birds, provided 

 with a covering of feathers to the under or inner surface of the 

 wing, though in nearly all cases this is now naked except for the 

 single rov/ of under-coverts, itself a disappearing quantity. 



Plumes on TJiird Finger. 



The third finger is ordinarily buried in the muscles of the 

 wing, but during development it projects freely, and in some cases 

 retains its distinctness in the adult. Where hidden, its free tip 

 extends nearly to the hind border of the wing ; and at this place 

 one or two additional plumes sometimes occur, interfering with 

 the regularity of arrangement of the under-coverts and wing- 

 quills. (PI. 515.) These irregular feathers are often a puzzle 

 to ostrich farmers. Dissections show that they belong to a 

 distinct series from either the under-coverts or wing-fjuills, the 

 quills crossing the phalanges of the third digit in the same manner 

 as the quills of the remiges cross the phalanges of the second dgit. 

 Without doubt, therefore, these additional feathers are to be 

 regarded as belonging to the third digit. 



In addition to the feathers at the ti]). single plumes are 

 Occasionally found set along the course of the third digit. They 

 may appear at any part of its length, and are altogether distinct 

 from the under-coverts. It is submitted that the tip feathers, 

 along with these along the length are representative of a time 

 when the ancestor of the ostrich had its third finger provided with 

 feathers, like those surviving on the bastard wing. Apparently 



