Anatoiiuj of the Kinyfishers. 119 



specific peculiarities which I have figured^ as much stress 

 has been laid on these structures. In fig. 17 the tendons are 

 all represented as arranged in the same position; ihejiexor 

 hallucis is to the right and is dotted^ the deep flexor is to 

 the left and is not dotted^ but that portion of it which 

 represents the vinculum is marked with longitudinal lines. 

 The hallux is to the left. Sundevall made one of the earliest 

 contributions to knowledge of the interesting divergences in 

 these tendons which occur among birds ; but his attention 

 was devoted specially to the Passerine foot^ while Garrod (2) 

 laid the foundation of a more general knowledge. According 

 to his account, and subsequent research has strengthened 

 his position, the normal Avian condition is that the Jlexor 

 haliucis tendon crosses the communis tendon to be inserted 

 to the hallux, but on its way sends a strong vinculum to the 

 communis. In certain birds, however, he showed that the 

 hallucis and communis tendons fused, and that from their 

 conjoined mass slips were given ofl:' to the digits, the hallux 

 slip arising markedly on the side of the communis tendon, 

 not on the side of the hallucis tendon. He supposed the 

 condition in Momotus, Merops, and Dacelo, where the com- 

 munis obviously supplied the hallux, and where the hallucis 

 tendon instead of supplying the hallux supplied other digits, 

 to be a simple derivative of the foregoing stage. In a King- 

 fisher chick, the species of which was undetermined, I found 

 the condition which Garrod thought intermediate between 

 the most common arrangement and that in Merops and 

 Dacelo. The hallucis and communis tendons fused, and 

 from the common mass the tendons to the four digits arose, 

 that of the hallux arising on the communis side. I think 

 that there is much more to be said as to the primitive 

 and derived conditions in birds generally, but for i!ie present 

 I may point out that, as the figures show, the typical King- 

 fisher condition, that most strikingly diff'erent from those 

 more common in other birds, is for the so-called hallucis 

 to supply digits 3 and 4, and for the so-called communis 

 to supply the hallux and digit 2. This is extremely 

 well seen in the eutaxic forms ffig. 17, p. 120, IV. to X.) ; 



