80 Trans. Acad. Sci. of St. Louis 
P. Chandler (Sutton, 1927, p. 189) and a rather extensive one 
in a beautiful photograph by Frank Pagan (Forbush 1927, pp. 
356-357). Likewise, I do not hesitate to say that if I had not had 
Peabody’s article in mind at the time the nests were found I 
might never have noted, in the field, these structures which seem 
so obvious in the photograph. 
The purpose of pavements seems clear. Though it may serve 
as a decoration, a concealing structure or in some such capacity 
as is attributed to snake’s exuviae or rags found at other birds’ 
nests, I believe its origin can be traced to two things: (1) the 
method of building the nest and (2) the Lark’s persistent de- 
mand for bare surfaces upon which to walk. Under the first 
point it should be remembered that the excavation is built back 
under an object on one side and has a long slope on the other. 
Nest material is not laid out to level up this slope but the pave- 
ment is (see Figure 10, also Plate VI, Fig. 2 and Plate VII, 
Fig. 1). Though Mouseley has shown, in one ease, that the 
pavement was entirely laid before any nesting material and Fig- 
ure 10 would not correspond exactly with his description, yet 
the purpose of the pavement could be the same in either case. 
And, too, a study of the construction of many nests seemed to 
show, that in some cases at least, pavement is laid after the nest 
is completed for much of the paving was above and over the 
outer edges of the nest material. The demand for a bare ap- 
proach to the nest and the consequent laying of a pavement to 
cover up intervening grass or nest edges seems to constitute 
another reason for this interesting structure. To substantiate 
this see Plate X, Fig. 2; Plate XI, Fig. 2; Plate XII, Fig. 2; 
Plate XV, Fig. 2. And some nests which had bare ground on 
all sides had no appreciable ‘‘pavement’’ (Plate XIV, Figure 2 
and Plate XV, Fig. 1). But, in order that the theory may not 
be too perfect, some nests which were surrounded by grass and 
should, under this hypothesis, have had the most extensive pave- 
ment had perhaps not more than a single, insignificant item (see 
Plate XVII, Fig. 1). In concluding it should be remarked that 
the Larks, if undisturbed, invariably approach the nest over the 
pavement (see Plate XXVIII, Figure 2). 
Eggs and egg-laying.—The ege of the Prairie Horned Lark 
has been described over and over in the evolution of ornithology 
from the “‘science’’ of odlogy. But, as far as I know, no one 
