344 MR. R. S. WRAY ON THE MORPHOLOGY [^^PI"- 5, 



at present, and has this advantage that it is applicable to both sides 

 of the wing, and reduces the terms used to a minimum. Professor 

 Flower and Dr. Sclater have done me the kindness of revising the 

 nomenclature^ for theremiges. The term "tertials" or "tertiaries" 

 has been abandoned, " cubitals " always including them when pre- 

 sent, because there is no way of absolutely distinguishing any definite 

 number of remiges as belonging to this special category. There is 

 certainly a distinction to be founded upon the arrangement of the little 

 muscular slips and tendons attached to the cubital remiges ; but it 

 would not be of much use in practice, owing to the difficulties in the 

 way of determining it with regard to many birds. 



The main points of interest'brought to light by the examination of 

 a considerable number of birds, some of almost every large group, 

 will be treated of, the wing of the Wild Duck, which is an extremely 

 good type, being first described in detail. The preparations in the 

 Natural-History Museum fully illustrate this paper, and most of the 

 accompanying drawings are taken from these preparations or from 

 essentially similar ones. 



The Wild-Duck's Wing. 



When the wing is extended for flight, the surfaces and borders 

 correspond to those of the primitive vertebrate limb, the preaxial 

 border being directed forwards, the postaxial backwards, and the 

 dorsal and ventral surfaces upwards and downwards respectively. 

 It is in this position the wing is best studied ; and when plucked of 

 feathers posteriorly it presents a fold of skin from the elbow to the 

 tip in which the flight-feathers and their principal coverts are 

 embedded ; these and their position are first described. 



When the wing is prepared as shown in the drawing (Plate XXIX.) 

 two main groups of quill-feathers are seen : — the secondaries or 

 CUBITALS attached to the ulna, and the primaries or metacarpo- 

 DiGiTALS attached to the manus. Of the latter, six, the Meta- 

 carpals (!-()), are attached to the metacarpus, and five, the Digitals 

 (7-11), attached one {addigital, 7) to phalanx 1 of digit iii., two 

 {middigilals, 8, 9) to phalanx 1 of digit ii., and two {predigitals, 

 10, 11) to phalanx 2 of digit ii. The distal predigital (11) is 

 always small, and is designated the remicle ; its relations, described 

 in detail later, show that it is as much a primary as the so-called 

 " spurious tenth " of many Passerines. The quill-feathers on the 

 cubitus stand out more or less at a right angle to the bone ; those on 

 the manus form a gradually increasing obtuse angle, till the last 

 feather lies parallel with the phalanx to which it is attached. 



The remiges are best numbered from the wrist-joint, proximallj' 

 for the cubitals and distally for the metacarpo-digitals ; because 

 with scarcely any exception reduction in number takes place at the 

 distal end of the manus and the proximal end of the cubitus. 



^ A somewhat similar nomenclature was proposed by Dr. Alix, ' Journal cle la 

 fiociete pbiloniatique,' 1874, p. 10. " Sur les phimes ou reuiiges des ailes des 

 oiseaux." 



