STRUTHIONES 503 



of the serratus profundus ; otherwise that muscle only con- 

 sists of the deeper portion which arises as two slips from the 

 last two cervical ribs and runs directly backwards to be 

 inserted on to the lower border of the scapula. 



The coraco-brachialis interims is largely tendinous ; its 

 origin, contrary to what is found in other Struthiones, just 

 extends on to the sternum. The origin of the biccjt.s is 

 peculiar ; it arises not only from the coracoid spine by a 

 rounded tendon, but also by a sheet of tendon edged with 

 muscle from the whole' of the coracoid and from just an 

 adjacent bit of the sternum. It is inserted on to both radius 

 and ulna. 



In the manus of Rhea, on the other hand, we have more 

 evidence of degeneration than in Stnithio. There are, in the. 

 first place, only twenty-one muscles at most, and some o! 

 these are much simplified. 



The muscles that appear to be totally wanting are (1) thf 

 extensor digitorutn coinmunis, (2) the pronator profiindiu. 



The extensor indicis is only represented by the belly 

 arising from the wrist. The flexor sublimis may possibly be 

 represented by a slip of muscle arising from the tendinous 

 edge of the flexor metacarpi ulnaris, which goes to be inserted, 

 partly by tendon, partly by fleshy fibres, on to the ulnare and 

 base of metacarpals 2 and 3. 



As in the ostrich the radio-metacarpalis ventralis arises 

 from the ulna. In Rhea there is a special peculiarity in the 

 presence of a muscular slip running from the tendon of the 

 extensor metacarpi ulnaris near to its insertion to the extensor 

 indicis. Finally the ectepicondylo-ulnaris is distinct. 



In the leg there is no femorocauda <l , the formula being 

 BXY + . The accessory femorocan <lal is enormous, and there 

 is a good struthious accessory adductor. Glut mix /iri/nus is 

 very large and overlaps biceps ; glut(cus V. is present and 

 large. 



In Dromaus 1 the rhomboideus superficialis and pro- 



' S. HAUGHTOX, 'Muscular Anatomy of the Emu,' P. E. Irish Ac. ix. 

 p. 487 ; Cr. ROLLESTON, ' On the Homologies of certain Muscles connected with 

 the Shoulder Joint,' Trans. Linn. Soc. xxvi. 1870, p. (ii)'.i. 



