26 COVERING OF THE BILL. 



the softest bill is found among the snipes, where it is skinnj' throughout, 

 and in typical snipes vascular and nervous at the tip, becoming a true organ 

 of touch, used to feel for worms out of sight in the mud. In all the duck 

 order, the bill is likewise soft; but there it is always terminated by a hard, 

 horny "nail," more or less distinct; and such horny claw also occurs in other 

 water birds with softish bills, as the pelican. An interesting modification 

 occurs in all, or nearly all, of the pigeon order; these birds have the bill 

 hard or hardish at tip and through most of continuity, but towards and at the 

 base of the upper mandible the sheath changes to a soft, tumid, skinny 

 texture, overarching the nostrils; it is much the same with most plovers. 

 But the most important feature in this connection is afforded by the parrots 

 and all the birds of prey ; one so remarkable that it has received a distinct 

 name : — Cere. The cere (L. cera, wax ; because it looks wax}') is a 

 dense membrane saddled on the upper mandible at base, so difl^erent from the 

 rest of the bill, that it might be questioned rather it does not more properly 

 belong to the head than to the bill, were it not for the fact that the nostrils 

 open in it. Moreover, the cere is often densely feathered, as in the Carolina 

 parroquet, in the bill proper of which no nostrils are seen, these being 

 hidden in the feathered cere, which, therefore, might be easily mistaken, at 

 first sight, for the bird's forehead. A sort of false cere occurs in some 

 water birds, as the jaegers, or skua-gulls (genera 280 and 279). The 

 tumid nasal skin of pigeons is sometimes so called ; but the term had better 

 be restricted to the birds first above named. The under mandible probably 

 never presents softening except as a part of general skinniness of the bill. 



(p.) The covering is either entire or pieced. In most birds it is entire; 

 that is, the sheath of either mandible may be pulled off whole, like the 

 finger of a glove. It is, however, in many birds divided into parts, by 

 various lines of slight connection, and then comes off in jDieces ; as is the 

 case Avith some water birds, particularly petrels, where the divisions are 

 regular, and the pieces have received distinctive names. The entire cover- 

 ing of both jaws together, is called rhamphotheca ; of the upper alone, rJdn- 

 otheca; of the under, gnathotheca. 



(c.) The covering is otherwise variously marked: sometimes so strongly, 

 that similar features are impressed upon the bones themselves beneath. 

 The most frequent marks are various ridges (L. pi. carinas, keels) of all 

 lengths and degrees of expression, straight or curved, vertical, oblique, hor- 

 izontal, lengthwise or transverse ; a bill so marked is said to be striate or 

 carinate; when numerous and irregular, they are called rugae (L. ruga, a 

 wrinkle) and the bill is said to be corrugated or rugose. When the eleva- 

 tions are in points or spots instead of lines, they are called punctce; a bill 

 so furnished is punctate, but the last word is oftener employed to designate 

 the presence of little pits or depressions, as in the dried bill of a snipe, 

 towards the end. Larger, softish, irregular knobs or elevations pass under 

 the general name of ivarts ov papilla}, and the bill so marked is papillose; 

 when the processes are very large and soft, the bill is said to be carunculate 



