DR. J. MURIE ON THE FORM AND STRUCTURE OF THE MANATEE, 153 
standing, is present, though greatly reduced in size. It arises as usual from the 
manubrium, but in front of the pectoralis major. Hence with a diminutive thin flat 
muscular belly, 3 inches long and 4 an inch broad, it proceeds forwards anteriorly to 
about a level with the outer border of the scapula, where it bifurcates (see fig. 9, St.7). 
The outer limb, a thin, strong, round tendon (shown in figs. 29, 30, S#.m), pierces the 
substance of the parotid gland, and is inserted into the paramastoid; the inner fork, a 
broadish aponeurosis, joins the deep cervical fascia of the neck, superficial to the carotid 
artery, and posterior to the thick fleshy digastric muscle. The shortening of the neck, 
great vascular rete, &c. give peculiar relations to the parts in the Manatee. 
From the unusually flat and wide arched form of the ribs, the serratus magnus muscle 
appears to have a different position from what it has in deep-chested animals, though 
in reality it departs little, if at all, from its normal situation; it is nevertheless com- 
paratively short and thin. The costal attachments are from the sixth rib forwards. 
On the scapula it is fixed underneath the rhomboideus the whole length of the 
vertebral border and to a triangular corner of the posterior inferior angle for about an 
inch in extent. Anteriorly in firm connexion with the fleshy scalene muscle it extends 
forwards, and is inserted into the outer and posterior surface of the enlarged transverse 
process of the atlas (Simg, fig. 29). The nuchal portion of the muscle has a twist upon 
itself, and is overlain by the broad belly and insertions of the scalenus, so that only a 
small segment of it is seen on the ventral surface of the neck when the parts are 
examined in position. 
The serratus in the Elephant’ is very massive, and extends backwards to the tenth 
or eleventh rib. Meckel’ says it is very small in Cetaceans, only fixed to at most four 
ribs; but my own researches agree rather with Carte and Macalister* and partly with 
Stannius*, in their being an apparent twisting or duplicity of the muscle and greater 
costal attachment. 
The /atissimus dorsi, as in the Cetacea, is entirely hidden by the superimposed layer 
of the panniculus, and it itself overrides in part the costal portion of the serratus 
magnus. On the surface of the chest it presents a broadish fan-shaped fleshy 
expansion, relatively short, upon the ribs from the fourth to the eighth; there is a 
deficiency of tendon or fascia at this costal attachment, the muscular fibres being well 
defined, and reaching no higher than on a level with the post-inferior scapular angle, 
below the sacro-lumbalis. It continues fleshy anteriorly to where it joins the teres 
major, the two muscles (as mentioned further on) being fixed together (La.d, fig. 8) to 
the middle of the shaft of the humerus. 
Abdominal.—Previous observers concur in noting the strange reptilian-like lengthening 
of the lungs and diaphragm, and consequent relatively altered position of the heart and 
upper or anterior abdominal viscera in Manatus; the same obtains in the two other 
BPr aan Os ? Vol. vi. p. 246. 3 Memoir, p. 224. 
* Under serratus anticus major, l. c. p. 13, and Rapp. p. 89. 
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