366 H. H. SWINNERTON. 
Swirski, the ‘ Sockelstiick,” or ‘processus posticus” of 
Wiedersheim, and the “processus ensiformis” of Ducret. 
For the sake of uniformity it may be called the post-coracoid 
process. 
Stage II (figs. 3 and 3a).—The skeleton, as a whole, is no 
longer concave towards the inner side, but both fin-plate and 
girdle are flat. The boundary between them is marked by an 
angle (fig. 3a, g. b.) due to the fact that the fin is no longer 
vertical, but stands out laterally. 
The glenoid line is still practically parallel to the long axis 
of the body. 
The fin-plate has undergone a considerable change in shape 
(cf. figs. 1 and 3), consisting mainly in a rounding off of the 
posterior angle due to a relative shortening of the posterior 
border (P.) and a growing out of the distal border. Near 
the front border (A) a large foramen has appeared, which 
marks off the region of the future first radial (r.). 
The girdle is still triradiate, but now all its radii le in the 
same plane, which is nearly vertical (8a, co., pr. p.), tending 
to slope inwards towards the mid-ventral line. The foramen 
for the branch of the fourth spinal nerve (fn. 4), which 
loomed so large at the previous stage, is now extremely 
small, and has taken up its final position near the base of the 
post-coracoid process, and may, therefore, be conveniently 
referred to as the post-coracoid foramen. 
The cartilage of the scapular region has grown forwards 
so that the ventral branch from the common trunk of the 
first three spinal nerves has become half surrounded. The 
deep notch thus formed (jn. 1—38) eventually becomes a 
foramen—the scapular foramen. 
The coracoid region has grown more rapidly than the 
scapular, as may be seen by comparing the region anterior to 
the post-coracoid foramen in figs. 1 and 3. ‘This growth has 
brought the anterior border (f. b.) close against a blood-vessel 
which supplies the ventral muscles of the fin. 
The mesocoracoid swelling, which at the previous stage 
was situated near the anterior margin of the coracoid, is no 
