284 PRO CELLARING. TKALASSIDROMA. 
eular sac, covered with scattered glandules ; stomach very 
small, elliptical, reversed ; pylorus on the left side ; intes- 
tine at first arched upward and to the right, before forming 
the duodenal curve, then rather long and narrow, with small 
coeca or none. Eyes rather small, as are the apertures of 
the ears. Legs slender, placed well forward ; tibia long, 
bare for about a fourth ; tarsus moderate or rather long, 
very slender, anteriorly reticulate ; hind toe extremely di- 
minutive, with a small conical claw ; anterior toes rather 
long, slender, scutellate, the third longest; interdigital mem- 
branes striate, and einarginate ; anterior claws small, little 
arched, compressed, rather acute. Plumage full, very soft, 
blended ; wings very long and narrow, primary quills very 
long, tapering, obtuse, the second longest : tail moderate or 
long, of twelve feathers, but varying in being graduate, 
rounded, even, or forked. 
The predominating colours are greyish-black and sooty- 
brown. The Petrels, during a great part of the year, roam 
over the seas, but in the beginning of summer collect into 
bands, and resort to particular breeding-places, to nestle in 
the crevices of rocks, under stones, or in holes in the turf. 
The single egg is white, large, and elliptical. The sitting 
birds are easily caught in their nests, and the young remain 
concealed until able to fly. On being seized, these birds, 
like the Fulmars, discharge the contents of their gullet, ge- 
nerally consisting of oil. They feed on oily and fatty sub- 
stances, Crustacea, and other objects, which they pick up as 
they skim over the water. They float lightly, fly in a ra- 
pid and buoyant manner, pat the water with their feet when 
hovering, are often seen about vessels in the ocean, and are 
held in dislike by sailors, who name them Mother Carey’s 
Chickens. One species only is common on the British coasts, 
but other three have been met with. 
819 . Thalassidroma Bulweri. Bulwer’s Petrel. 
Tail cuneate ; bill and feet black ; plumage deep sooty- 
black, on the lower parts slightly tinged with brown ; second- 
ary coverts paler ; length ten inches. 
First described and figured by Sir William Jardine Bart., 
and Prideaux J ohn Selby, Esq. in the second volume of their 
Illustrations of Ornithology ; afterwards, in the fourth vo- 
