PROFESSOR WOOD ON THE NECK- AND SHOULDER-MUSCLES. 
87 
scapula ?, viz. the “ levator claviculoe ,” which we shall find, when we discuss its homo- 
logues in the lower animals, to have something of a correlation with the occipito-sca- 
pular, placed at the opposite pole from which we started. 
Before following this direction, however, I will notice a further indication of trans- 
mutation in the direction of the splenitis muscle, i. e. backward, which may be con- 
sidered to have some relation to the formation of the occipito-scapular in the human 
subject. In Haller’s ‘ Disputationum Anatomicarum Selectionum ’(1733, vol. vi. p. 589), 
F. .Waltiier gives a description of a muscle connected with the splenii , under the name 
of the “ musculus singularis splenii accessorius” vel “ adjutor splenii .” This muscle 
corresponds entirely with a variety I have found in four male subjects out of 41, and in 
three females out of 29, in a total of 70, in the years 1866, 1867, and 1868 (given in 
the ‘ Proceedings of the Royal Society’ of these years respectively). One of the females 
was the subject of fig. 7 (Plate IX.), in whom the variety was found as a flat, ribbon-shaped 
muscle (y), lying upon and parallel with the fibres of the splenitis colli . Its upper 
attachment was placed upon the transverse process of the atlas, between the tendons of 
the levator anguli (f) and splenitis colli ( li '). It was hardly to be distinguished at this 
place, without dissection, from the fibres of insertion of the latter muscle ; but, as it de- 
scended, it became more distinct and differentiated, and was finally separated from both 
the splenii by the intervention of the tendon of the serratus posticus superior (s). It 
1 was about 6 to 7 inches long, by \ an inch wide, passed under the rliomboideus minor 
muscle (r), and ended below in spreading tendinous fibres, which became blended, 
partly with that of the origin of the rliomboideus major (R), and partly with that of the 
serratus. The muscle has been described also by Mr. A. Macalister under the name 
of the “ rhomb o-atloid” (Notes on Muscular Anomalies in Human Anatomy, in the 
‘Proceedings of the Royal Irish Academy, April 23rd, 1866). 
This formation, I believe, indicates the first loosening or differentiation of the splenitis 
muscle in the direction of the formation of an occipito-scapular in the human subject. 
We shall find that, in the Mole, the whole of the splenitis may become attached to the 
scapula (see Plate X. fig. 11, li). 
In the subject of fig. 7 was also found a triple insertion and an extended origin of the 
levator anguli scapulae. The cervical digitations of the muscle were continued down as 
low as the sixth transverse process. The three lowest digitations were inserted by two 
separate slips (F), the uppermost (larger) into the base of the scapula opposite the supra- 
spinous fossa ; and the lowest (smaller), conjointly with and superficial to the tendon 
of the rliomboideus minor (r), into the triangular commencement of the scapular spine. 
This formation indicates an approach to that found in some of the Carnivora, in whom 
the muscle corresponding to the human levator anguli scapulae is inserted into the sca- 
pular spine close to the occipito-scapular (see Plate X. figs. 14 & 15 
I next proceed to describe a highly important human muscular variety, the levator 
claviculoe , to which I have before referred, the formation of which the slips previously 
described and shown in figs. 5 & 6 evidently foreshadow, and which, it may be said, 
I 
