THE MUSCULATURE OF THE TRUNK. 277 



ively to the longissimus dorsi and sacro-lumbalis } and 



continuing, with the intervention of certain neck muscles, 

 from the cranium to the end of the dorsum of the tail. 

 But a great simplicity still may exist, as in Tailed Batra- 

 chians (e.g. Menopoma and Menobranchus) , where, with- 

 out the intervention of any such neck muscles, a simple, 

 or more or less tendinously intersected muscular mass 

 extends from the skull directly to the end of the dorsum 

 of the tail. This dorsal muscle may be reduced to a 

 mere rudiment, as in Emys, where it runs between the 

 transverse and neural processes and the carapace >: 

 (Elem. Anat., pp. 322, 323). 



Among the group of muscles we are now examining, 

 the deep layer of muscles of the back in the Eaven, the 

 sacro-lumbalis forms the outer portion of that close- 

 fitting, tendo-rnuscular sheet seen extending between 

 the anterior margin of the ilium to the root of the neck, 

 and is to be only with difficulty differentiated from the 

 longissimus dorsi, which is to be found between it and 

 the dorsal neural spines. 



It arises, 1 quite tendinous, from the anterior margin 



1 The system of musculature of the dorsal region in birds, Professor 

 Gadow defines as the " I. DORSO-SPINALE MUSKELN," and proposes 

 to divide this " System des M. sacro-spinalis " into four parts, viz. 



-1. M. ILIOCOSTALIS; 2. M. LONGISSIMUS DORSI; 3. M. CERVICALIS 



ASCENDENS ; and 4. M. TRANSVERSO-OBLIQUUS. Of these, the first 

 represents the muscle we now have under consideration, or the 

 SACRO-LUMBALIS, and for it Gadow sees the following synonymy, 

 viz. : 



"1. M. ILIOCOSTALIS. 



Costo-cervical (pt.). Yicq d'Azyr, 1772, p. 580, No. 2. 



Aeusserer Riickgrats-Strecker. Tiedemanu, 217. 



Der Ruckenrnuskel. Merrem. 



Opisthotenar (Aeusserer Bauch). Meckel, System, p. 291, No. 1. 



Sacro-lumbalis. Owen ; Gurlt, p. 18 



