632 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



part of the hypocoracoid. It laps over the hypercoracoid and bor- 

 ders the anterior half of the hypercoracoid foramen, as seen from the 

 oater side of the shoulder girdle; but as seen from the inner side, the 

 hypercoracoid entirely incloses its foramen, protecting- it anteriorly, 

 however, b}" a very narrow margin. 



The postclavicle is a long, simple ray of bone carried ])y a project- 

 ing plate from the upper end of the clavicle. 



The hypoclavicle is a very wide, thin plate, with an anterior rod of 

 bone reaching to the lower end of the clavicle and inclosing a large 

 fenestre. From just in front of the lower actinost a straight ridge 



iG. 5.— Right shoulder girdle of MACRORHAMPHOsrs sagifus from outf.r girdle. For let- 

 tering SEE Fig. 1. 



runs o])liquely forward to near the lower edge of the hypocoracoid, 

 where it turns at a sharp angle, and, following the edge of that bone, 

 runs horizontally forward to its end at the clavicle. 



The lower actinost is ver}^ much enlarged. It cuts a large space 

 from, and continues down over the outer surface of, the hypocoracoid 

 nearly to its middle. It ends in a sharp point. The others are some- 

 what pointed below, and grow smaller upward. There is a raised 

 condyle on the hypercoracoid resembling the heads of the actinosts 

 for the first ra} s of the pectoral to work on. All but the lowest 

 actinost are attached to the hypercoracoid. 



