VESTIGIAL EPISTERNA 
Fic. 22.—Shoulder girdle of Ornithorhynchus. ¢ 
clavicle ; e.c, epicoracoid ; es 
m.8, Manubrium sterni ; sc, scapula; st, sternebra. 
of Man.) 
cs . 
Fia. 23.—Episternum of an em- 
bryo Mole. (After A. Gotte.) 
cl, Clavicle ; es’, central por- 
tion of the episternum ; es”, 
lateral portion of the same 
r.c, costal ribs ; st, sternum. 
(The figure was constructed 
from two consecutive hori- 
zontal sections, ) (From 
Wiedersheim’s Structure of 
Man.) 
to the ventral ends of 
' Prac. Zool. Soc. 1865, p. 56 
1c’, c, First, second, third ribs ; cd, 
‘and es”, interclavicle (episternum) ; m.c, metacoracoid ; 
(From Wiedersheim’s Structure 
and are attached to the clavicles, and are no doubt to be regarded 
as the same structure. Probably in many 
mammals the manubrium will be found 
to be partly made up of corresponding 
rudiments. In any case, vestiges of an 
episternum in the shape of two minute 
ossicles have been discovered in Man, 
lying in front of the manubrium. They 
have been termed ossa suprasternalia. 
In Man and in the Mole the paired 
nature of the episternum is clearly 
apparent. It has been suggested that 
this structure in its entirety belongs to 
the clavicles, just as the sternum belongs 
to the ribs; 7.e. that 1t formed out of the 
approximated and fused ends of the 
clavicles. Dr. Mivart' figured a good 
many years since a pair of ossicles in 
Mycetes, lying in one case between the 
ends of the clavicles and the manubrium 
sterni, and in another example anterior 
the clavicles. Gegenbaur has figured a 
ie 
