PERONEAL MUSCLES IN BIRDS. 1045 



It is clear that the Colymboniorphfe present no coherent 

 picture, the Petrels being sharply marked off from the others 

 by the relative dominance of the P. brevis. 



Pelargomorph^. 



CiCONIIFORMES. 



S t egan opod e s. 



Phaethontidfe. Fha'ethon. — P. longus normal but rather small, 

 ■with superficial and deep origin, broad anchor and slip to III. 

 P. brevis normal, with long muscular origin and short tendon with 

 usual flattened insertion. 



Sulidse. Sula bassana. — P. longus normal and large but with 

 only superficial and slight fascial origin. Broad short anchor and 

 slip to III. P. brevis absent. 



Phalacrocoracidfe. Phalacrocorax (? species). — P. longus normal 

 and large ; origin, anchor and slip to III as in S-ida. P. brevis 

 strong but very short, arising only from the lower end of the 

 tibial shaft, distal to the fibula, and with normal insertion by 

 flattened tendon. 



Fregatidse. Fregata. — Peroneus longus large and strong but 

 origin practically only deep from the whole length of fibula and 

 adjacent surface of tibia on side turned from the brevis. Broad 

 anchor and good slip to III. P. brevis minute but quite distinct 

 and normal, with long slender belly and tendon passing under a 

 fibrous bridge and then flattening out to pass to usual insertion. 



Pelecanidas. Pelecanus.—l have not had a recent opportunity 

 of examining a Pelican, but from my old notes I find that the 

 P. longus is large and normal with the usual anchor and slip to 

 III, and that the P. brevis is present but minute. 



Ardese (from these I exclude Scopus and Bcdceniceps). 

 A rdea egretta, A . herodias, A . herodias lessoni, A .inirpxirea. Ardetta 

 viinuta. Nycticor ax gardenia N.violaceusi^ examples). Botaurus 

 stellaris, Cancroma zelodonL— In all these the P. longus is fairly 

 large (text-fig. 180), but has only the superficial origin with slight 

 fascial origin. The anchor is rather long, broadens out, and at 

 least in one case {A . herodias lessoni) was in two slips. The P. brevis 

 is well developed usually from about three-quarters the length of 

 the shaft but chiefly from the fibula. The long tendon passes 

 through a fibrous bridge and then flattens out to the normal inser- 

 tion. I think there must be some mistake in Gadow's statement 

 that the P. brevis is absent in Ardea. I find that its presence is 

 one of the differences between Herons and Storks. In Ardetia 

 minuta and Cancroma it is particularly strong. 



Scopidae. Scopus umbretta. — The P. longus is large with 

 superficial and slight fascial origin, broad anchor and good slip 

 to TIL The P. brevis is either actually absent or represented by 

 a very small ligament. 



Baltenicipitidse. Balccniceps rex. — P. longus a sti'ong broad 



