Page 642. 
204 ON CERTAIN MUSCLES OF BIRDS. 
It is absent in :-— 
Strepsilas interpres. Scolopax rusticula. 
Inmosa rufa. Gailinago scolopacina. 
Totanus calidris. gallinula: 
solitarius. ~  Calidris canutus. 
Gambetta flavipes. Tringa cinelus. 
Machetes pugnaz. 
The Gavie possess the ambiens, the femoro-caudal, the semiten- 
dinosus, and the accessory semitendinosus; the postacetabular portion 
of the tensor fascie is slightly developed in Larus and Lestris, but not 
in Sterna; the accessory femoro-caudal is present, though small, in 
Sterna, but absent in Larus and Lestris. 
Species examined. 
Lestris antarcticus. Larus glaucus. 
Larus argentatus. Sterna hirundo. 
The Procellariide must be considered under two Civanes, the 
Storm-Petrels and the true Petrels. 
The Storm-Petrels possess the femoro-caudal, the accessory 
femoro-caudal, the semitendinosus, the accessory semitendinosus, 
and the postacetabular portion of the tensor fascie#; the ambiens 
were present in a black one, but quite absent in three specimens of 
a light-grey species. 
Species examined. 
Procellaria pelagica ?* Procellaria fregata ?+ 
The true Petrels possess the ambiens, the femoro-caudal, and the 
semitendinosus ; the postacetabular portion of the tensor fascise is very 
small, or absent, and the accessory femoro-caudal is present in all but 
Bulweria bulwert. 
[The accessory semitendinosus is absent. ]} 
Species examined. 
GZstrelata lessoni ? Bulweria bulweri. 
Prion vittata. Puffinus anglorum. 
Daption capensis. 
and some unnamed specimens. 
* [This is, in all probability, Oceanites oceanica. The true Procellaria pelagica 
lacks the accessory semitendinosus muscle.—ED. ] 
+ [An uncertain species. —ED.] 
t [Lhis passage has been corrected ; “semitendinosus” (on p. 642) being a mis- 
print for “ femoro-caudal,” and the absence of the accessory semitendinosus muscle 
in the birds omitted in the original.—Eb. ] 
