284 PROF. OWEN ON THE ANATOMY 



second cervical vertebrae inclusive, immediately beyond which it again becomes fleshy, 

 and expands to be inserted into the occipital ridge : this portion is the digastrique or 

 biventer capitis of Cuvier. 



Spinalis dorsi (PI. XXXIII. fig. 1. p). — ^The displacement of the dorsal portion of the 

 preceding muscle and the longissimus dorsi brings into view the spinalis dorsi, which is a 

 well-developed and distinct muscle in the Apterijx. Origin. By two long, narrow, flat- 

 tened tendons (p, I & 2.) from the spines of the eighth and seventh dorsal vertebrae : 

 these pas.s obliquely downwards and forwards, expanding as they proceed, and terminate 

 in two fasciculi of muscular fibres : the posterior bundle passes forwards beneath the 

 anterior one, and inclining inwards and upwards, divides into two portions, inserted by 

 long tendons into tlie spines of the second and first dorsal vertebrae (^1*) ; it then sends 

 a few fibres forwards to join the outer and anterior fasciculus, which is partly inserted 

 by a slender tendon into the spine of the last cervical vertebra : the rest of the fibres of 

 the second fasciculus join the portion of the longissimus dorsi (m) which is implanted into 

 the posterior oblique process of the last cervical vertebra. The three inserted tendons 

 of the spinalis dorsi are also the medium of attachment of fibres continued from the 

 multijidus spina;, beneath them. 



Multifidus spinee (PI. XXXIII. fig. \. q) . — The series of muscles so called arises by fleshy 

 fibres from the transverse processes of the five last dorsal vertebrae, which pass upwards, 

 forwards and inwards, to be inserted by four flat tendons into the spines of the seventh 

 to the third dorsal vertebrae inclusive, and by the tendons of the spinalis dorsi into the 

 two anterior dorsal spines. 



Ohliquo-spinales (PI. XXXIII. fig. 3. r). — The removal of the multifidus spines brings 

 into view a series of long, narrow, flat tendons, coming off from the spines of all the dorsal 

 vertebrae, and slightly expanding as they proceed forwards and obliquely downwards and 

 outwards ; they become fleshy half-way from their origin, and are inserted into the poste- 

 rior oblique and transverse processes of the six anterior dorsal vertebrae, and into the 

 posterior obhque processes of the three last cervical vertebrae. 



Interspinales (PI. XXXIII. fig. .'i.s). — The interspinales muscles do not exist in the 

 region of the back, unless we regard the preceding oblique fibres as a modified repre- 

 sentation of them. The most posterior fasciculus of muscular fibres, which is directly 

 extended between the spinous processes, commences at the interspace of the spines of 

 the two last cervical vertebrfe, and the series is continued as far as the vertebra dentata. 



Interarticulares (PI. XXXIII. fig. 3. t). — The muscles which form the more direct con- 

 tinuation of the obliquo-spinales are continued from the posterior oblique or articular 

 processes of one vertebra to the posterior articular process of the next in front. 



Obliquo-transversales (PI. XXXIII. fig. 3. v). — A third series of deep-seated interver- 

 tebral muscles is situated external to the preceding, and passes obliquely between the 

 upper transverse process and the posterior articular process of the vertebra in front. 

 These fasciculi appear to be a continuation of the multifidus spina in the neck. 



