686 



DR. P. CHALMERS MITCHELL ON THE 



crossing over the profundus, runs to the haUux, but sends a long 

 slender branch which joins the profundus tendon just before 

 tha,t divides for the digits. The condition corresponds with what 

 Gadow (16, p. 195) calls type I. The hallucis tendon crosses 

 over the profundus to reach the hallux, but sends a vinculum to 

 it. In Storks and Herons tlie condition is essentially similar, but 

 in the former group the vinculum is stronger and may be in 

 separate slips ; in Scojncs and the Herons the vinculum is much 

 more slender and may be absent. For comparison I figure the 

 condition in a Stork (text-fig. 131, S), a Heron (text-fig. 131, A), 

 and in JBalcenicej)s (text-fig. 131, B). 



Text-fiff. 131. 



Diagram of Deep Flexor Tendons in A, Nifcticora.r ; B, Balceniceps : 

 S, Leptoptilus. 



The longus hallucis tendon is in outline, t\\& flexor 'profundus is shaded. 

 1. Hallux. 2, 3 & 4. 2nd, 3rd & 4th digits. 



Popliteus. — There was only one of these little muscles stretch- 

 ing across between the head of the fibula and the tibia. In 

 Leptoptilus I noted two. 



Summary of Muscular Anatomv. 



Garrod's hope, excited by his extraordinarily interesting pioneer 

 work, that muscular anatomy would furnish a sure clue to the 

 classification of birds has not been fulfilled. Garrod relied chiefly 

 on the presence or absence of certain muscles which he found to 

 vary from group to gi-oup. Gadow, who has attempted on a 

 complete scale to apply to the system Garrod's group of muscles, 

 using the additional facts made known by Beddard and other 

 writers, appreciated that as these muscles Avere a common heritage 

 of all birds, the presence of any of them in any group of birds 

 could not be taken as a guide to the systematic position of that 



