318 



DR. H. GADOW ON THE SPECIES OF RHEA. [Mar. 17, 



thin spindle-shaped semitendinous head from the pubic spine. 

 This additional little slip is probably the last trace of the ambieus 

 muscle, whch is now generally lost by the Passerine birds. 



The case above described is one way in which this muscle gets lost ; 

 in other cases, e.g. Ciconia and Phoenicopterus, the reduction does 

 not begin by its tendon becoming attached to neighbouring tendons 

 in the knee-region, but the whole muscle shows a diminution of its 

 tendon and belly to a mere thread, till at last this also disappears, 

 e. g. in Abdimia and Xenorhynchus. 



Digestive Organs. 



The digestive organs of Rhea darwini did not present any re- 

 markable differences from those of Rh. americana, and a comparison 

 of the relative dimensions was not advisable because of the different 

 age of the specimens examined. 



The hepatic and pancreatic ducts, together with the shape of the 



Fig. 7. Eh. americana. The duodenal loop and pancreas, with the fli-st aud 

 second pancreatic ducts {py and ^j„), and showing the hepato- 

 enteric duet {he), the cystico-enteric {cc), and tlie hepato-cystico- 

 enteric duct (lice). 



Fig. 8. Kk. darwini, J. The duodenal loop is represented too wide in this 

 flKure. 



pancreas of Rhea darwini S , showed an arrangement somewhat 

 different from that of the Rhea americana described by myself in 

 the ' Jenaische Zeitschrift.' See figures 7 & 8. 



Respiratory Organs. 



There are some diff'erences in tlie shape of the posterior margin of 

 the upper larynx, as will be seen in the following wooducts : — 



