ANIMAL MECHANICS. 427 



Muscular Type of Wings of Ostrich and Rhea. 







Ostrich 



Ostrich 



Rhea 



Rhea 



Rhea 







No. 1 ' 



No. 2 ' 



No. 1 



No. 2 



No. 3 







(female). 



(female) . 



(male). 



(female). 



(male). 





Scapular. 



Per cent. 



Per cent. 



Per cent. 



Per cent. 



Per cent. 



I. 



Trapezius, .... 



4- J 4 



3.27 



3-5° 



4-75 



2.71 



2. 



Rhomboideus, . . . 



2 06 



0. 54 



0. 87 





1-93 



3- 



Serratus magnus, . . 



i . 16 



3-93 



2. 62 



2.13 



2.97 





Abductors. 













I. 



Deltoideus, .... 



33- io 



28.21 



15-72 



15.64 



16 91 



2. 



Pectoralis avium, . . 



3-53 





16. 16 



17.77 



15-23 



3* 





12 <8 



6* 27 



8 H 



A 08 



8. 38 



4- 



Spinatus, .... 



3.28 



4-47 



3-49 



7. 11 



9-94 





Hcxors. 













I. 



Triceps longus, . . 



2.97 



4-47 



7.42 



4-50 



6 -33 



2. 



Subscapularis, . 



12.37 



10.78 



9.61 



10. 90 



3-°9 



3- 



Latissimus dorsi, . . 



5- 15 



4.03 



6.55 



5- 6 9 



3.74 





Extensors. 













i. 



Biceps humeri, . . 



3. 93 



4.58 ) 



6.55 



6.88 



7 • 35 



2. 



Brachioeus, .... 



1.31 



1.52 / 





1 . 1 8 



1. 29 





Adductors. 













I. 



Coraco-brachialis, . 



1.41 



1.09 



6.99 



3-32 



9-93 



2. 



Pectoralis major, . . 



1 r . 46 \ 



13.07 



11.79 



!3-5° 





3- 



Pectoralis minor, . . 



o.55 I 



10 20 





IOO 



IOO 



IOO 



IOO 



IOO 







Oz. av. 



Oz. av. 



Oz. av. 



Oz. av. 



Oz. av. 





Total weight, . . 



19-82 



9i8 



229 



4-22 



3-88 



It will be seen from this Table that the Ostrich and Rhea 

 belong to distinct types, well marked, but agreeing with each 



as in other birds, and possesses a single tendon only ; whereas in the Emu and 

 Cassowary the Obturator internus is double, viz. : — 



(a.) with puboischial origin, and inserted an inch higher up than (/3) 



on the femur, so that the tendons cross each other. 



(/3.) with ilioischial origin. 



These muscles are quite distinct in their actions, and must have some unknown 

 relations to peculiarities in the gait and habit of the Emu and Cassowary, which 

 do not occur in the Ostrich and Ehea. This muscular peculiarity alone place 

 the Emu and Cassowary far remote from all other birds. 



