II SHOULDER BLADE AND LOCOMOTION 
37 
the spine, the prescapular lamina, is most extensively developed in 
such animals as per- 
form complex move- 
ments with the fore- 
limbs. The Sea Lion 
and the Great Anteater 
are cited by Professor 
G. B. Howes as ex- 
amples of this pre- 
ponderance of the an- 
terior portion of the 
scapula over that which 
lies behind the spine. 
The general shape of 
the scapula varies con- 
siderably among the 
& 1 Wyant 
¥ SAR ul 
SU AN 
Fic. 27.—Right scapula of Dolphin (Tursiops twrsio). 
a, Acromion ; af, prescapular fossa ; ¢, cora- 
coid ; gc, glenoid cavity ; pf, postscapular fossa. 
(From Flower’s Osteology.) 
different orders of mammals ; but it always presents the characters 
Fic. 28.—Side view of right half of 
shoulder girdle of a young Hchidna 
(Echidna hystrix). x%. a, Acro- 
mion; ¢, coracoid; cb, coracoid 
border ; c/, clavicle; css, coraco- 
scapular suture; ec, epicoracoid ; 
gb, glenoid border; ge, glenoid 
cavity ; ic, interclavicle ; pf, post- 
seapular fossa; ps, presternum ; Ss, 
spine ; ss, suprascapular epiphysis ; 
ssf, subscapular fossa. (From 
Flower’s Osteology.) 
thus presents (in this feature) 
mentioned, which are nowhere seen 
among the Sauropsida except among 
certain Anomodonts, which will be 
duly referred to (see p. 90). The 
most conspicuous divergences from 
the normal are to be found in the 
Cetacea and the Monotremata. In 
the former the acromion is approxi- 
mated so nearly to the anterior 
border of the blade-bone that the 
prescapular fossa is reduced to a 
very small area; and in Platanista 
the acromion actually coincides 
with the anterior border, so that 
that fossa actually disappears. In 
the Whales, too, the scapula is as 
a rule very broad, especially above ; 
it has frequently a fan-like contour. 
In the Monotremata the acromion 
also coincides with the anterior 
border of the scapula; but the 
sameness of appearance which it 
to the Cetacean scapula is appar- 
