220 



MK. P. CHALMEliS MITCHELL ON SO-CALLED 



that ill tlie eutaxie pigeons the biceps slip tends to be highly 

 specialized. In D the normal pigeon-condition is present ; in A, 

 E, and F, the normal insertion with a considerable origin by 



Fig. 3. 



I, Geopha.;ps plumifera. II. Geopelia tranquilla. III. Phlogoenas cruentata, 

 showing differentiation of brevis tendon into a, /3, and y slips of Fiir- 

 bringer. 



aponeurosis from the wing-membrane ; in a, B, and C, the 

 extreme development with a long tendon at either end. 



Deltoides patagialis. — In tig. 2, Pat., the normal pigeon-condi- 

 tion is shown. The belly of the muscle divides into two peaks, 

 that to the longus being certainly smaller but quite well marked. 

 The distal end of the brevis is divided only into a distal slip 

 running to the extensor, and made known by Fiirbringer as 

 'alpba'; the two slips 'beta' and 'gamma' are not difBeren- 

 tiated, but are represented by a single diffuse sheet. In A, a, 

 D, E, and F the longus slip is proportionately rather smaller; in 

 B__and C it is exceedingly small, almost absent, and the small 



