Shufeldt — Uobert Collett on Pteri/cnmhns hrumu Fries. I, 



Supraclavici-b, Parker, (Scapula, Owen), is rather long and narrow ; 

 the width (9 inni. ) being equal to one-fourth the length (36 mm. ). 



Postclavici.e, Parker, (Epicoracoid, Owen), is normal, with long sty] i- 

 form process. 



Cokacoid, Parker, (Radius, Owen), which in lirama is large and of 

 broad oval outline, suggesting the immense coracoid in Lampris, is here 

 in Pterycombus much narrower and directed more anteriorly. Its length 

 in the specimen now being examined is 53 mm., the greatest width 20 

 mm. Along its mesial margin it is formed partly in membrane, and 

 exhibits a little below its center an oval notch, which is quite circular in 

 lira inn. Just within its outer margin two elevated longitudinal rays 

 radiate from the actinosts; the superior one, which is the smaller, is quite 

 short, while the lower one, which passes somewhat internal to the margin 

 of the hone, is continued almost to its anterior end. The pelvic gikdle 

 is small, slender hut otherwise normal. 



Ribs. These number 23, of which twenty of the posterior pairs exhibit 

 an unusual development. They are broad, hollow, and together form a 

 bony wall without interstices, as each rib is so broad that its posterior 

 margin overlaps the edge of the rib next behind it. They are relatively 

 short, being attached to the downwardly produced apophyses in such a 

 manner that their truncated superior parts reach to the center of the 

 vertebra'. 



First rib is articulated with the third vertebra, and is short, being only 

 slightly broader at its head than it is at its free extremity (therefore about 

 normal ). Second and third ribs are somewhat broader at their articular 

 ends, but are rapidly reduced in size as the free ends are approached. 

 finally terminating in an elongated delicate ventral extremity. 



The fourth to the twenty-third ribs are very characteristic. Atypical 

 one. the eighteenth, is here shown in the cut, and may he described as 

 follows: The vertebral extremity, which is intimately articulated at the 



external aspect of the parapophysis, is 

 almost square or cubical in form, and is 

 hollowed out up as far as its head. This 

 excavation is continued as a groove for a 

 little distance down along the internal 

 border of the rib, and thereafter termi- 

 nates in a long, extremely attenuated free 

 ending. At its broadest part the superior 

 excavation is nine millimeters broad, 

 measured in the antero-posterior direc- 

 tion, while its thickness internally is 

 rather less than 5 mm.; its height (13) 

 somewhat exceeds its width, and consti- 

 tutes not quite one-third of the entire 

 length of the rib (44 nun. ). 

 In thefive posterior pairs of ribs the postero-superior angle of the exca- 

 vation is produced as an apophysis, flexed caudalwards, and which is, 

 particularly on the ultimate rib, long and slender, projecting outward 



Fig. 1. 

 Ribs of Pterycombus brama. 



(Nat. size.) 



