THE EXTEENAL BTETTCrrEE OF BIEDS. 



163 



may be entirely reticulate. Earely the tarsus may be " greaved " 

 (continuously sheathed) in front and yet scutelliplantar. 



The upper surface, or dorsum, of all the toes— called the 

 acropodium — is almost always scutellate. Their under surface 

 is in general minutely marked, but may develop small wart-like 

 structures — "pads " or tylari — as may be seen in Hawks. 



Glows. — Every digit of a bird's foot is provided at its end with 

 a horny claw, more or less curved and pointed at its extremity, 



QtclL 



DiAGEAM OF Epidermal. Covering of Tarsus and Digits. 



a. Reticulate form (Plover). J. Scutellate and reticulate form (Pigeon), 

 c. Booted or greaved laminiplantar form (Eobin). d. Scutellate lami- 

 niplantar tarsuB (Cat-bird — Mimiis carolinensis). 1 <-4 1. Digits, trs. 

 Tarsus. Stcl. 3rd digit from tarsus to end of claw. (After Coues.) 



except that the hallux, when in a rudimentary condition, may 

 be clawless. Claws vary as to length and strength. They are 

 exceptionally long and all straight in the Jacanas, especially 

 that of the hallux. They are at their maximum of strength, 

 as well as much curved and acutely pointed, in the Hawk and 

 other birds of prey. They are but little pointed in such birds 

 as the Fowl and the Pigeon, but most obtuse of all in the 

 Grebe. 



M 2 



