144 Degeneration in the Ostrich 



Prof. T. H. Morgan {I.e. p. 50) seem pertinent : " Moreover, the fact that 

 recent work has made clear that genes generally have more than a single 

 effect on the organization opens wide the door of suspicion, for the 

 observed morphological progress might be a by-product of influences 

 that have other and important, though unseen, effects." 



A structural narrowing might be anticipated where the number of 

 rows of coverts is in course of reduction if the wing of the ostrich as a 

 whole be undergoing degeneration, and from comparison with other 

 Ratitae a change of this nature seems likely. A shortening of the wing 

 also may be looked for in correlation with a reduction in the number of 

 remiges and coverts to the rows as a whole, but no relationship of the 

 kind is yet manifest, even though the former vary from 44 to 38. The 

 matter would probably assume a different aspect however if the remiges 

 commenced to undergo reduction at the distal or free end of the row, 

 instead of being restricted to the proximal or elbow end as at present. 



Remiges or Wing Quills. 



Closely associated with the coverts are the remiges or wing-quills. 

 They comprise the familiar white plumes of the ostrich and a few parti- 

 coloured feathers from each end of the row, the so-called hyocks or 

 fancies. They are the most valuable of all the ostrich plumes, and from 

 a farming and breeding point of view call for more consideration than all 

 the other kinds combined. Quality in them counts for far more than 

 quantity. The latter however has an importance, seeing that to a large 

 extent the number of remiges also determines the number of coverts 

 alternating with them. 



The wing plumes have been counted on large numbers of both 

 northern and southern birds and the results published ^ It is shown 

 that on the wing of the northern bird they vary from 33 to 39, while on 

 the southern bird they fluctuate from 33 to 42, the latter number since 

 increased to 44. In a mixed assemblage, uninfluenced by selection, both 

 northern and southern countings form an approximately normal curve 

 of fluctuating variation, with the mode at 36 and the arithmetical mean 

 about 36*5. Before the present investigations only one southern bird 

 with the high number 42 was known, while the numbers 41 and 40 were 

 extremely rare. These few scarcely influence the average, and for 



1 " Breeding Experiments with North African and South African Ostriches ; IV. In- 

 creasing the Number of Plumes ; Degeneration and Restoration," Dept. of Agric, Union 

 of South Africa, Bull. No. vii. 1918. 



