48 
second cervical vertebre 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 Cuyier, 
Spinalis dorsi (Pl, XII. fig. 1. p).—The displacement of the dorsal portion of the pre- 
ceding muscle and the longissimus dorsi brings into view the spinalis dorsi, which is a 
well-developed and distinct muscle in the Apteryx. Origin. By two long, narrow, flat- 
tened tendons (p, 1 & 2.) from the spines of the eighth and seventh dorsal vertebra : 
these pass 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 the spines of the second and first dorsal vertebrze (p 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 
multifidus spine, beneath them. 
Multifidus spine (Pl. XII. fig. 1. q)—The series of muscles so called arises by fleshy 
fibres from the transverse processes of the five last dorsal vertebrie, which pass upwards, 
forwards and inwards, to be inserted by four flat tendons into the spines of the seventh 
to the third dorsal vertebra inclusive, and by the tendons of the spinalis dorsi into the 
two anterior dorsal spines. 
Obliquo-spinales (Pl, XII, fig. 3. r).—The removal of the multifidus spine brings into 
view a series of long, narrow, flat tendons, coming off from the spines of all the dorsal 
vertebra, 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 vertebre:, and into the 
posterior oblique processes of the three last cervical vertebre. 
Interspinales (Pl, XII. fig. 3. s).—The interspinales muscles do not exist in the region 
of the back, unless we regard the preceding oblique fibres as a modified representation 
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 vertebrae, and the series is continued as far as the vertebra dentata. 
Interarticulares (Pl, XII. 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 (Pl. XII. fig. 3, v).—A third series of deep-seated intervertebral 
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 spine in the neck. 
