178 DR. R. W. SHUFELDT ON [-^PI"- 1> 



the mesially situated spinalis dorsi, and the sacro-lumhalis upon its 

 outer side. And its origin seems to be in the sacro-lumbar region, 

 where it arises, for the most part, from the diapophyses of the 

 vertebrae ; but as it passes to the middle of the back, and the cervical 

 region beyond, its attachment becomes insertional, and liy tendinous 

 points of development it makes fast to the apices of the postzyga- 

 pophyses, and to the dorsal surfaces of the ribs on their outer sides. 

 Origin and insertion apparently are more or less blended in mid- 

 dorsal region, but this muscle is distinctly insertional in the cervico- 

 dorsal and cervical regions, while stdl more anteriorly the longissimiis 

 dorsi becomes specialized and goes to form muscles that will next be 

 described. 



.^S. Complexiis. — This is a most powerful muscle here, con- 

 stituting as it does the antero-median insertion of the longissimus 

 dorsi upon tlie skull. We may consider it as coming off from more 

 or fewer of the post-axial vertebrae, and it is inserted into the 

 posterior border of the parietal bone, as well as into the hinder 

 surface of the cranium below it. All these muscles of the neck are 

 quite intimately blended, more especially the two or three at present 

 under consideration. 



.59. The Trachelo-mastoid is another muscle which continues the 

 lotiffissimus dorsi forwards to the skull behind, being situated 

 external to the last, and inserted principally into the os occipitale 

 externus. 



60. Transversalis colli is the last of the three muscular fasciculi 

 which insert themselves into the posterior aspect of the cranium, as 

 the forward prolongations of the longissimus dorsi. It attaches 

 itself at a point lower than any of them, being inserted into the 

 basioccipital near the rectus anticus major, and intimately associated 

 on its outer side with the cervicalis ascendens. This muscle 

 is the comjilexus minor of Mivart, as found by him in Parson's 

 Chameleon. 



61. Sacro-linnbalis. — In our present subject this muscle arises 

 from the superficial aspect of the hinder end of the ilium of the 

 corresponding side, and, passing as a narrow band over the pelvic 

 region, it commences to broaden as it covers the ribs. From thence 

 on to the neck it has a width greater than the spinalis doi'si and the 

 longissimus dorsi together, but mesiad it is not so thick vertically, 

 while it gradually becomes thinner as it passes outwards. As in the 

 case of the two muscles just mentioned, the general direction of its 

 fibres is directly forwards, and its insertion is found to be upon the 

 dorsal surface of each rib, for more or less their inner thirds. These 

 insertions are tendinous and very firm, while the ventral surface of 

 the muscle itself is quite intimately blended with the intercostals, 

 and more posteriorly with the quadratus lumhorum. On its inner 

 side, for its entire length, it is easily dissected from the longissimus 

 dorsi, the two muscles being quite distinct, while anteriorly it 

 merges into the cervicalis ascendens, a muscle which constitutes its 

 proper continuation forwards. 



62. Cervicalis ascendens. — This muscle is handsomely developed 

 [32] 



