THE RUBY -THROAT ED HUMMING BIRD. 
197 
2 twelfths in breadth at the base. The right lobe of the liver is much larger 
than the left, the former being 5 twelfths in length, the latter 4 twelfths. 
The whole length of the head is li inches, of which the bill is 10 twelfths. 
The upper mandible is slightly concave beneath in its whole length, the 
lower a little more deeply concave, the edges 
of both thin, those of the lower erect and 
overlapped by the upper. The nostrils are 
covered by a very large projecting mem- 
branous flap, feathered above. The tongue 
is, to a certain extent, constructed precisely 
in the same manner as that of the Wood- 
peckers. The basi-hyal bone is II twelfths 
long, the apo-liyal bones 2 twelfths, the 
apo-hyal and cerato-hyal together 1 inch 2 
twelfths, the glosso-liyal or terminal bones 
41 twelfths. There is no uro-hyal bone, any 
more than in the Woodpeckers, and the glosso-hyal is double at the end. 
The horns of the hyoid bone are thus greatly elongated, recurving over the 
occiput, near the top of which they meet, and thence proceed directly 
forward, in mutual proximity, lodged in a deep and broad groove, along the 
middle of the forehead, until near the anterior part of the eye, where they 
terminate, fig. 3. The crura of the lower mandible, fig 4, do not meet until 
very near the tip, and from the inner and lower surface of each 
near the junction or angle, there proceeds backward a slender 
muscle, which is attached to the hyoid bone at the junction of 
the apo-hyal and cerato-hyal, whence it proceeds all the way to 
the tip of the latter, the muscle and bone being enclosed in a 
very delicate sheath, which is attached to the subcutaneous 
cellular tissue between the nostrils. The tongue, properly so 
called, moves in a sheath, as in the Woodpeckers ; its length is 
10 twelfths. When it is protruded, the part beyond this at the 
base appears fleshy, being covered with the membrane of the 
mouth forming the sheath, but the rest of its extent is horny, 
and presents the appearance of two cylinders united, with a deep 
groove above and another beneath, for the length of 3 twelfths, 
beyond which they become flattened, concave above, thin-edged 
and lacerated externally, thick-edged internally, and, although lying parallel 
and in contact, capable of being separated. This part, being moistened by 
the fluid of the slender salivary glands, and capable of being alternately 
.exserted and retracted, thus forms an instrument for the prehension of small 
