THE OSTEOLOGY OF AMIURUS CATUS. 303 



The foramen (for), however, which usually occurs between them, is 

 still present and indicates that while the scapular portion is very 

 small the coracoid has reached a very great degree of development, 

 meeting with its fellow in the middle line, and being united to it by 

 sutural union. This coracoid has been described (by Huxley for 

 instance) as the clavicle, but this must be a mistake, for in a well 

 macerated skeleton, this portion separates perfectly from the portion 

 in front, the clavicle, showing that these two are not the same. If 

 the extension of the coracoid, towards the middle line, seen, for 

 instance, in the Gadidce, be continued still farther, the arrangement 

 which obtains in Amiurus will result. The upper surface of these 

 coalesced bones presents no point worthy of special notice, but on the 

 ventral surface of the outer portion the following points may be 

 noticed. First of all there is the bridge-like process (br) which 

 extends over to the anterior ridge on the under surface of the infra- 

 clavicula, and at its base a high ridge (r) is to be seen which dimi- 

 nishes rapidly as it passes inwards, and is soon lost. Slightly exterior 

 to this is a small rod-like process (rp), which articulates with the 

 inner basalia of the fin, and from its base a fine spicule of bone (sp) 

 passes transversely across to the posterior margin, its anterior portion 

 giving an articular surface to certain of the radialia. This spicule 

 forms an arch through which a muscle runs and just below its 

 anterior point of attachment is the foramen between the scapular 

 and coracoid portions. 



From the arrangement of the articulations of the fin, and from 

 general characters, I am inclined to refer to the scapula, the thin 

 triangular portion, which is well marked off, and whose limit on the 

 exterior edge would be a line drawn from the base of the rod-like 

 process for the inner basale. The spicule-like arch belongs probably 

 to the coracoid portion. 



The fin consists of two principal rows of elements. The proximal 

 row consists of three elements, two osseous and one cartilaginous. 

 The posterior element (the fin being erected) is osseous, a rather 

 slender rod tipped with cartilage at either end. Proximally it does 

 not reach the pectoral arch, a small cartilage intervening. This is 

 Huxley's 1 metapterygial basale. The next element, proceeding 



1 Huxley.— Anatomy of the Vertfthrates. London, 1871. 



