Pelvic Girdles of Mureenosaurus plicatus. 431 
edge, which bears no tubercle such as otcurs in Cryptoclidus 
(see this Magazine, ser. 6, vol. xv. p.°337, fig. 2A, t). The 
median portion of the ventral bars had already begun to 
row back to form 4 junction with the anterior prolongations 
of the coracoids, but were still separated from them by a con- 
siderable interval; other pectoral girdles in tie collection 
show this junction. The scapule had not yet quite met in 
median symphysis, and anteriorly were separated from one 
another by a wide V-shaped interval. In life this space was 
wholly or partially closed by the clavicular arch, which 
unfortunately is wanting in this specimen. The scapule 
anteriorly curve inwards and upwards in such a way that, 
with the clavicles, they formed the anterior wall of the thorax. 
The general form of the coracozds (cor) is shown in the figure 
(fig. 1). Between the glenoid surfaces the bones are very 
thick and massive, and unite in a strong median symphysis 
Pectoral girdle of Murenosaurus from above. sc, scapula; cor, coracoid ; 
h, humerus. About =}; nat. size. 
about 5 centim. deep at the thickest part. In this region the 
visceral surface of the coracoids is concave from side to side, 
forming an are of a circle whose radius is about 28 centim. 
Behind this strong transverse ridge the visceral surface is 
depressed, owing to the rapid thinning of the bone, which, 
except near the outer border, is less than a centimetre thick. 
In this thin posterior region the coracoids meet at an angle 
of about 120°. The outer concave border is somewhat 
thickened, but is not produced backwards and outwards into 
31* 
