280 PROF. OWEN ON THE ANATOMY 



pass forwards and join those of the preceding muscle, to be inserted into the scapular 

 integument. 



Obs. The three preceding muscles are broad and thin, but well-defined ; they would 

 appear to influence the movements of the rudimentary spur-armed wing through the 

 medium of the integument, as powerfully as do the rudimental representatives of the 

 true muscles of that extremity. 



There are also two muscles belonging to the cutaneous series, and inserted directly 

 into the bones of the wing. One of these, the Dermo-ulnaris (PI. XXXI. i), is a small, 

 .lender, elongated muscle, which takes its origin from the fascia beneath the dermo- 

 costalis ; its fibres pass backwards, and converge to terminate in a very slender tendon 

 which expands into a fascia, covering the back part of the elbow-joint. 



Use. — To extend the elbow-joint and raise the wing. 



The Dermo-humeralis (PI. XXXI. k) is also a long and narrow strip, deriving its origin 

 from scattered tendinous threads in the subcutaneous cellular tissue of the abdomen : 

 it passes upwards, outwards and forwards, and is inserted fleshy into the proximal part 

 of the humerus, which it serves to depress'. 



Muscles of the Trunk. 

 A. On the Dorsal Aspect. 



The muscles on the dorsal aspect of the vertebral column in Birds have only of late 

 years received any attention from Comparative Anatomists : they have been mentioned 

 rather than described by Tiedemann and Meckel : Carus has given a side-view of the 

 superficial layer of muscles in the Sparrow-hawk ; their best description is contained in 

 the second edition of the ' Lecons d'Anatomie Comparee' of Cuvier. 



The muscles of the back are in general so feebly developed in birds of flight, that they 

 were affirmed by Cuvier to be wanting altogether in the first edition of the ' Lecons :' 

 and this is almost true as respects their carneous portion, for they are chiefly tendinous 

 in birds of flight. In the Struthious birds, and in the Penguin, in which the dorsal 

 vertebrae are unfettered in their movements by anchylosis, these muscles are more fleshy 

 and conspicuous ; but they attain their greatest relative size and distinctness in the 

 Apteryx. 



From the very small size of the muscles which pass from the spine to the scapula and 



' In Mammalia the cutaneous muscles form a more continuous stratum than in the Apteryx and other birds, 

 and hence have been grouped together under the common term panniculus cartiosiis ; they have also, in general, 

 both their origins and insertions in the integument ; but in Birds the integument supports so extraordinary 

 an abundance of the epidermic material under the form of feathers, that the muscles destined to its especial 

 motions require a more fixed attachment from which to act. The Rhinoceros, in which the integuments, 

 from the thickness and density of the corium, are in a similar condition as regards the resistance to be overcome 

 by their peculiar muscles, presents an analogous condition of the panniculus camosus, having it divided into 

 several distinct muscles, most of which take their origin from bone or fasciae attached to bone. 



