SKELLY—SKIMMER 867 
Toe ; but in Cypselus the number never exceeds 3, being reduced 
during embryonic development. The proximal phalanx of the 
fourth toe is resorbed, while the 2nd and 3rd phalanges of the 
third toe, and the original 3rd and 4th of the fourth fuse together 
respectively. The same number of phalanges obtains in Pany- 
ptila. Further reduction in the number of toes begins with the 
hallux, which, as may be gathered from what has been already 
stated, represents almost every intermediate condition from being 
the strongest, as in Accipitres, to total loss. The second toe is 
absent in Struthio only, though its malleolus is present, but in a 
very degenerate condition. This Bird indeed seems to be on the 
way to becoming one-toed, for though the fourth still exists, long 
and functional, its phalanges decrease in length and strength towards 
the extremity, and the terminal one is frequently reduced to a mere 
nodule, devoid of a claw. Such an example has therefore already 
reached a one-hoofed condition. Cholornis, a rare form from Thibet, 
of doubtful affinity, seems to offer the only instance of the loss of 
the fourth toe, which is said to be reduced to a mere stump. The 
proportional length of the phalanges, especially when the reduction 
in length affects the basal and next following phalanges without the 
terminal, is of some taxonomic value, for a special account of which 
reference may be made to the account in Bronn’s Thier-reich (pp. 
508-521), but above all to Kessler’s Osteologie der Vogelfiisse, in 
the Bulletin of the Naturalists’ Society of Moscow for 1841 (pp. 
467, 628). 
SKELLY, or SHELLY, a local name for the CHAFFINCH. 
SKIDDAW, another form of Kippaw (see GUILLEMOT). 
SKIDDY, otherwise SKITTY-Cock, a name applied to the 
Moor-HEN and Water-Raltrt. 
SKIMMER, the English name bestowed by Pennant?! in 1773 
on a North-American bird which had already been figured and 
described by Catesby 
(B. Carol. i. pl. 90) under 
that of “ Cut-water,’— 
as it appears still to be 
called on some parts of 
the coast,2— remarkable 
for the unique forma- 2g 
tion of its bill, in which Ruyncuops. (After Swainson.) 
the maxilla, or so-called upper mandible, is capable of much vertical 
1 “J gall it Skimmer, from the manner of its collecting its food with the 
lower mandible as it flies along the surface of the water” (Gen. of Birds, p. 57). 
2 Other English names applied to it in America are ‘“*Razorbill,” ‘‘ Scissor- 
bill,” and ‘‘ Shearwater.” 
