ON CERTAIN MUSCLES OF BIRDS. 203 
ciliaris the femoro-caudal is present, but very slender. In @. grallarius 
it is absent. The ambiens is present in the three above-named species, 
but it is peculiar in being sometimes but imperfectly developed. It 
_erosses the knee very externally, and was quite normally developed 
in a specimen of @. bistriatus and in one of @. grallarius. In another 
specimen of . grallarius it was lost anteriorly on the fasciz covering 
the knee; and in one of @. superciliaris it crossed the knee, but sent 
off a slip on the in- and outside to join the investing fascia. 
In the Cariamide the semitendinosus, the accessory semiten- 
dinosus, and the postacetabular portion of the tensor fasciz are 
present. The ambiens was absent in a specimen of Cariama cris- 
tata, but present in one of Chunga burmeisterit. The femoro-caudai 
was absent in both. The accessory femoro-caudal was present in 
Cariama cristata, though extremely small. It was absent in Chunga 
Among the Gruide, Grus antigone possesses the ambiens, the 
femoro-caudal (very small), the accessory femoro-caudal (small), the 
semitendinosus, the accessory semitendinosus, and the postacetabular 
portion of the tensor fasciz, as does also Anthropoides virgo. 
Among the Eurypygide, Rhinochetus jubatus possesses the ambiens, 
the femoro-caudal (extremely thin), the semitendinosus, and the 
_ accessory semitendinosus ; the accessory femoro-caudal is absent. 
The Rallide possess the ambiens, the femoro-caudal, the accessory 
femoro-caudal, the semitendinosus, the accessory semitendinosus, and 
the postacetabular portion of the tensor fasciz. 
Species examined. 
Rallus aquaticus. - Ocydromus sylvestris. Page 641. 
Aramides cayennensis. Porphyrio madagascariensis. 
Porzana americana. melanotus. 
carolinensis. Gallinula chloropus. 
Crez pratensis. 
The Gralle possess the ambiens, the femoro-caudal, the semiten- 
dinosus, the accessory semitendinosus, and the postacetabular portion 
of the tensor fascis ; the accessory femoro-caudal may be present or 
absent. 
It is present in :— 
Glareola, sp. Charadrius hiaticula. 
Numentus arquatus. r Himantopus nigricollis. 
—— pheopus. Parra africana. 
Hematopus niger. 
It is sometimes present (very small), sometimes absent, in :— 
Charadrius pluvialis. Vanellus cristatus. 
