1062 DR. p. CHALMERS MITCHELL ON THE 



Strix Jiammea. Speotyto cunicularia. — There is no ti'ace of the 

 P. longus in any of the Owls. The P. brevis is enormous, but 

 visually arises only from the tibia below the fibula. In Strix 

 Jiammea (text-fig. 186) it is relatively longer, arising from all 

 the fibula distad of the insertion of the biceps, from the adjacent 

 tibial surface, and from the tibia distad of the end of the fibula. 

 In Athene it is equally long. The stout tendon flattens out after 

 passing through a fibrous bridge (absent in Strix) and is inserted 

 in the normal fashion to the proximal end of the tarsus-metatarsus. 

 Its chief action is to rotate the foot on the tibial shaft so as to 

 depress the great toe side and elevate the foui-th digit side. It 

 comes into action after the enormous tibialis anticus has flexed 

 the foot. 



a p r i m u 1 g i . 



Steatornithidse. Steatornis caripensis. — The P. longus is absent. 

 The P. brevis is large and strong, with origin from high up the 

 shaft from both fibula and tibia and fairly long tendon which 

 fiattens out to usual insertion. 



Podargida?. Podargus cuvieri. JSfyctidromus alhicollis. ^Ego- 

 theles novce-hollandicE. — In Podargus the P. longus has a broad 

 superficial origin Avith no fascial or deep origin. It gives off a 

 broad anchor and is continued as a slender slip to III. The 

 P. brevis is stronger than the longus. It arises from fibula, and 

 tibia just below the insertion of the biceps, and its rounded 

 muscular belly passes into a stout tendon which fiattens out to 

 the usual insertion. In Ryctidromus the P. longus is practically 

 the same as in Podargus, but the P. brevis is absent. In uEgo- 

 theles novce-hoUandice the P. longus is absent, and the P. brevis 

 is well developed, as in Steatornis. 



Caprimulgidae. GajJrimidgus europceus. — The P. longus is lai'ge 

 with superficial, fascial, and deep oi-igins. It has a broad anchor 

 and a good slip to III. The P. brevis is absent. 



1 have followed the usual arrangement of the genera of Capri- 

 mulgi that I have examined, and certainly I do not propose to 

 rearrange them simply on the evidence of the peroneal muscles. 

 It is plain, however, that so far as these muscles are concerned, 

 Podargt(,s has remained in the primitive condition, with both 

 muscles present and normal ; Steatornis and ^Egotheles have 

 specialized in the same direction as the Owls, by losing the 

 P. longus ; Caprimulgus and Nyctidromus present a condition 

 very aberrant amongst Coraciiform bii'ds, and by retaining the 

 P. longus and discarding the P. brevis recall the condition which 

 frequently occurs in the great assemblages which I have already 

 passed in review. 



Cy pseli. 



Cypselidse. Cypselus apus. — The P. longus is absent. The 

 P. brevis is large and strong, from the proximal end of the shaft 

 including the head of the fibula and adjoining area of the tibia 

 down three-quarters of the shaft, then a very strong tendon 



