DR. J. MURIE ON THE FORM AND STRUCTURE OF THE MANATEE. 139 
The posterior common ligament within the spinal canal was not examined. 
I observed in nine or ten of the anterior dorsal vertebre an extra ligament. This 
passes as a more or less strongish band from the posterior surface or border of the 
lower portion of the vertebral lamina to the anterior border of the transverse process, 
and over the articulating process. From the fourth to the seventin vertebra it is well 
marked, but is less distinct in the succeeding ones. 
The capsular ligament is divided by a strong interarticular spur from the inter- 
vertebral. The two synovial cavities are very distinctly separate. 
Of the true ligamentous bands lashing the cost to the spinal elements, each stellate 
ligament is only imperfectly divided into two bundles. 
The anterior costo-transverse ligaments of human anatomists are wanting. 
But in all the ribs there are developed short, but immensely strong, middle costo- 
transverse ligaments. ‘These are situated deeply, and pass in an oblique direction 
between the ribs and the transverse processes. They are covered by a portion of the 
external intercostal muscles, and partly surrounded by the intervertebral plexus of 
vessels. 
Every one of the eighteen posterior costo-transverse ligaments is remarkably broad 
and strong. Along with the stellate ligament the middle costo-transverse ligament 
prevents the rib rotating too far forwards. 
3. Limbs, Pelvis, and Ligaments. 
Vrolik’s portraiture (pl. 3) and remarks (/. c. p. 69) on the progressive development 
of the pectoral limb are sufficient for practical purposes. In his larger specimen the 
ossific centres of the phalanges, three to each and two to the thumb, are not quite so 
rigidly defined as in that coming under my own observation. The ligaments connecting 
the limb-segments are very simple, the flattened condition of the bones obviating much 
differentiation ; and each joint is uncommonly lax. The tendon of the subscapularis 
pierces and greatly strengthens the shoulder-joint. 
The pelvic bones of two males at different ages have been delineated in the ‘ Bijdragen’ 
(pl. 5); and, excepting in greater circularity of the central mass, my young male agreed. 
In the older female ossification had proceeded further. The figure of the bone is 
furcate or semilunar, therefore differing from the adult male, where it has an irregular 
diamond-shape. ‘The extremities of the horns are cartilaginous, the rectus abdominis 
muscle being inserted between (vide fig. 50); and the posterior concave border has 
likewise a cartilaginous rim, to which the ischio-coccygeus is affixed. On the inner 
border the transversus perinei &c. are attached. This edge, therefore, represents the 
ischium, the tuberosity being that turned rearwards; the anterior cartilages tipping 
the cornua are respectively pubis and ilium. The surfaces of the bone are smooth, 
and indeed slightly concave; but all limb-structure is absent. The relative dimensions 
of the pelvis were :—male, } inch in diameter; female, about 1} inch in long and 1] inch 
