1-10 Mr. P. C. Mitchell on the 



resembles this — the concentration is carried slightly further, 

 /3 and 7 alone being distinct at their insertions, while above 

 there is a single round tendon. 



The forms showing these conditions may obviously be placed 

 in a series — the diastataxic forms led by Ceryle maxima being 

 at one end, the eutaxic forms culminating in Cei/x and Ceryle 

 inda being at the other. Beddard (4) has rightly remarked 

 that the Alcedo type was anatomically the simplest of those 

 with which he dealt, and obviously the C. inda type is still 

 simpler. But it is no necessary conclusion that in an ana- 

 tomical series the simpler structure is the more primitive. In 

 the case of the alar tendons, Fiirbringer has shown that the 

 brevis tendons are to be regarded not as extensions of their 

 muscles, but as differentiations of the originally diffuse alar 

 fasciae into which these muscles were inserted, the muscles 

 themselves being originally cutaneous slips. From this point 

 of view it is plain that the diffuse undifierentiated condition 

 of C. maxima is the most primitive of the series; C. alcyon 

 shows a differentiation of this diffuse structure by the 

 appearance of thickenings, presumably along the lines of 

 strain ; Sauropatis, Halcyon, and Cittura show, so to speak, 

 a cutting away of the unnecessary diffuse fasciae betv^een 

 the thickenings, with the result that the latter appear as 

 independent tendons. In the other eutaxic forms these 

 tendons become simplified by concrescence until the Passerine 

 single-tendon condition is reached ; but the distal ends may 

 still retain traces of the differentiation into a, j3, and 7. 

 Thus it would appear that in this case, as in the case of the 

 splitting of the deUoides patagial'is, the eutaxic forms display 

 the higher stages of progressive specialization. Curiously 

 enough, in this case, as in that of some structures among 

 Pigeons, the degree of differentiation reached by eutaxic 

 forms shows interesting resemblances to well-known features 

 of the Passerine structure. 



Scapalo-humerales anterior et posterior. — The condition of 

 these muscles in the Kingfishers is that found in most groups 

 of birds. As in Dacelo (fig. 12), both muscles are present ; 

 they meet at their origin from the scapula, but remain quite 



