322 DU. GADOW ON THE ANATOMY OF PTEr.OCLES. [Miir. 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 ot the heads of the m. 

 flexor perforatus dig. ii. et iii. 



5. " The presence of lumbricales in the foot." The muscle vyhich 

 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 Katitse, and has been described by Meckel, 

 although he gave no name to it, in his ' System der vergleich. Anat.' 

 iii. p. 388, and in his 'Archiv fiir Anat. u. Physiol.' pp. 2/8 & 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 longns in Pterocles 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 Pterocles; 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 Pterocles 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, Talegalla, and Plover " {Parker). 



The crop {ingluvies) of Pterocles is a simple dilatation of the an- 

 terior and lateral walls of the oesophagus, 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 oesophagus, 

 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 ccso[)hai;us, slightly widened 



