262 THE MYOLOGY OF THE RAVEN. 



which in man are entirely absent. These muscles are 

 the numerous muscles which move the tail, and which 

 may attain a vast bulk, as in the Cetacea and in Fishes. 

 To describe these muscles in detail would rather 

 come within the scope of a treatise on the compara- 

 tive anatomy of animals than within that of the 

 present work. Here, however, it may be stated that 

 the enormous coccyx of the Porpoise is provided not 

 only with the dorsal muscles which continue on backwards 

 the erector spinas (with its main divisions) from the 

 occiput to the tail end, but also possesses a ventral 

 muscular mass (extending forwards as far as the middle 

 of the thorax), which mass is divisible from above down- 

 wards into two antero-posteriorly extended masses — 

 together constituting, as it were, a ventral (and here 

 sub vertebral) reflection of .the erector spinse. The same 

 appearance occurs in some Reptiles and in Tailed 

 Batrachians, where the ventral muscles of the tail repeat 

 below, the dorsal masses above. But these Batrachian 

 caudal muscles are not subverteljral — not the con- 

 tinuation backwards of subvertebral ones of the trunk, 

 but direct continuations backwards of the abdominal 

 muscles, as is also the case in most Fishes " {Elem. Anat., 

 pp. 323, 324). 



It may be said here d pro])os to these remarks that 

 the subvertebral caudal muscles are, as a rule, but feebly 

 developed in the higher groups of birds, unless some 

 special habit of the form demands them, as we know 

 to be the case in the AVoodpcckers. 



The following muscles in the trunk of the Raven 

 present themselves for our examination : — - 



123. The complexus. 125. The flexor capitis inferior. 



124. The rectus capitis anticus 126. The rectus capitis posticus 



minor. major. 



