142 Field Columbian Museum — Geology, Vol. II. 



marked ridge, also for muscular attachment, traversing the anterior face 

 obliquely, and terminating near the lower, outer angle of the process. 

 Fiirbringer says of these processes in the pterosaurs: "Proc. lateralis und 

 Proc. medialis, namentlich aber der erstere sind sehr kraftig entwickelt 

 und prominieren insbesondere proximal so stark, dass das zwischen 

 ihnen befindliche Caputhumeri sogar theilweise gegen sich zuriicktreten 

 kann; dagegen ist — sehr im Unterschiede zu den meisten Sauropsiden, 

 namentlich aber den Theromorphen und Dinosauriern — der Proc. later- 

 alis wenig in die Lange entwickelt, indem er gewohnlich nur das proximal 

 % bis y$ des Humerus einnimmt. Diese Konfigurationen lassen darauf 

 schliessen, dass die Mm. supracoracoideus (supracoracoscapularis, scapulo- 

 humeralis posterior und subcoracoscapularis) eine relativ hohe Entfaltung 

 besassen, der M. pectoralis dagegen keine so abnorme Starke darbot, 

 wie es von vornherein von einem fliegenden Thiere erwartet werden 

 konnte, und der M. deltoides nur mittelstark entwickelt war."* 



The shaft below the lateral process is of nearly uniform width. A little 

 above the middle of each bone, on the inner or ventrolateral side, starting 

 from precisely the same place, and lying transversely, there is a slender 

 bone, less than a millimeter in width, and about twelve millimeters in 

 length, preserved. I do not know what it is, nor whether it really 

 belongs in this position, though the similarity of the bone on the two 

 sides suggests that it does. It may be an ossified tendon. . . Because 

 of the position in which both humeri are lying, the distal extremity 

 has been transversely compressed, effacing the articular surfaces to a great 

 extent. There seems to be a small depression on the inner epicondyle. 



MEASUREMENTS OF HUMERUS. mm. 



Length '. 87 



Least width of shaft 5 



Least width of lateral process - 17 



Width of lateral process distally 25 



Width of humerus through lateral process 42 



Width of median process 5 



Ulna. PI. XLII, Fig. 2. The bones of the left forearm lie nearly in 

 position, and in contact with the distal end of the humerus; those of the 

 right side have been slightly separated, the radius detached and removed 

 proximally. The left ulna is lying nearly upon its outer side, partly over- 

 lapping the radius; that of the right forearm has been compressed dorso- 

 ventrally. The bone is slightly expanded at the extremities. There are 

 two, nearly confluent, articular surfaces at the proximal end, the smaller, 

 nearly circular one, on the inner side, nearly confluent with the large, less 



*Jenas. Zeitschrift, 1900, p. 363. 



