322 DR. GADOW ON THE ANATOMY OF PTEROCLES. [ Mar. 21], 
The four other muscles are well developed in most birds, as - 
Prof. Garrod has stated over and over again, and as the dissection 
of any fowl will show. 
4. “The special relation of the tendon of the ambiens (when pre- 
sent) to the fibular head of the flexor perforatus secundus tertii 
digiti.”” The distal end of the ambiens muscle, when typically deve- 
loped, always forms the continuation of one of the heads of the m. 
flexor perforatus dig. 11. et 111. 
5. ‘The presence of lumbricales in the foot.” The muscle which 
Mr. Haswell takes to be the representative of the lumbricales muscles 
of mammals has not “ hitherto escaped the notice of anatomists,” and 
it is not “ peculiar to the Pigeons,” since it is also present in many 
other birds, e. g. the Ratitee, and has been described by Meckel, 
although he gave no name to it, in his ‘System der vergleich. Anat.’ 
ii. p. 388, and in his ‘Archiv fiir Anat. u. Physiol.’ pp. 278 & 279. 
With regard to the muscles of the leg, I am unable to point out 
any typical differences between Sand-Grouse, Fowls, and Pigeons. 
The absence of the m. flexor hallucis longus in Péerocles is of no 
importance, as this muscle is generally absent in birds which have 
no hallux or only a small one, and, moreover, as the absence of this 
toe itself affords no family character. Of course there are many 
points, e. g. the mode of origin and the arrangement of the tendons 
of the muscles, and even the absence of the m. plantaris and of the 
m. peroneus profundus, which are noteworthy in Péerocles; but all 
these things are variable, and give us no characters which hold good 
throughout the Gallinaceous or the Columbine group. 
It is the same with the m. ambiens: this muscle is present and 
well developed in Péerocles and most probably in all the Rasores ; 
in the Pigeons its presence is variable. 
Of all the other muscles connected with the leg, there is none that 
shows any practical difference between Sand-Grouse, Pigeons, and 
Fowls, and even (if we include them in our comparison) the Plovers. 
On the whole, however, the myology of Pterocles indicates that it 
is more nearly allied to the Pigeons than to any other group of birds. 
VISCERA. 
“The trachea is cartilaginous; and it has at its bifurcation what 
the Grouse is bereft of, viz. a pair of laryngeal muscles, as in the 
Pigeons, Tulegalla, and Plover” (Parker). 
The crop (ingluvies) of Pterocles is a simple dilatation of the an- 
terior and lateral walls of the cesophagus, without any constriction in 
the middle line, although it is broader than long. Its walls are very 
thin on its anterior parts, and show longitudinal folds and glands ; 
the dorsal part, the prolongation of the dorsal half of the cesophagus, 
is thicker and slightly muscular, the external sheath consisting of 
transverse, the inner one of longitudinal smooth muscular fibres. 
In the Pigeons the crop is different. It consists of two lateral 
and symmetrical dilatations of the lateral walls, whilst the middle 
part is simply the continuation of the cesophagus, slightly widened 
