634 PROCEEDINGS OF THE XATTOXAL MUSEUM. vol. xxv. 



The cliivicle shows externally us a wide triangular plate reachino- 

 nearly to the pectoral, its anterior end descends ])orderino- the g'ill 

 opening as usual. From the inside the clavicle appears about three 

 times longer than deep. From the inner upper edge a thin plate of 

 bone turns down to the hypercoracoid. 



The In^percoracoid does not nearly contain its foramen, but is 

 assisted above by the inner plate of the clavicle. 



A simple postclavicle is attached to the posterior end of the clavicle 

 directly above the hypercoracoid. It is a very slender ray of bone 

 bending sharply down to a level with the lower pectoral ray and thence 

 reaching horizontally far])ack and ending as a tine filament. 



The hypocoracoid is a nearly square thin plate, with a slender 

 process running from its lower anterior corner at a right angle with 

 its anterior edge to the lower end of the clavicle. From its upper 

 posterior corner obliqueh' toward the lower anterior corner the lower 

 actinost cuts in and subdivides it. 



The upper ray of the pectoral works directly' upon the hypercora- 

 coid. Three of the actinosts are borne by the hypercoracoid and one 

 by the hypocoracoid. 



All of the inner elements of the shoulder girdle are extremely thin 

 delicate plates, but slightl}' ossified, and generally strengthened l)y 

 osseous ridges. 



