Auatomij of the Kingfishers. 115 



conditions of the muscle and the eutaxy or diastataxy, but, 

 so far as it goes, the width is more often greater in the 

 eutawic forms. The instances in the figures do not show the 

 contrast in its most marked state. 



Caud-illo-flexorius. — The accessor!/ semi-tendinosus is 

 possibly represented by a few fibres in Dacelo ; it is absent 

 in the others. The semi-tendinosus in all is inserted to the 

 tendon of the semi-membranosus ; it is rather wider in those 

 forms in which the femoro-caudal is wide (figs. 13, 14, s.t.). 



Ischio-flexorius {semi-membranosus) in all is larger than 

 the semi-tendinosus, and is inserted to the tibia by a flat 

 tendon (figs. 13, 14, s.m. ; fig. 15, semi-m.). It also varies 

 in width with the width of the femoro-caudal, the increased 

 width being specially marked, in the eutaxic Ceryles. 



Biceps in all is a strong muscle with a very wide origin 

 and the usual sling. 



Ischio-femoralis {obturator exHernus) differs slightly but 

 irregularly in the extent of its origin from the pelvis, being 

 rather shorter in some of the eutaxic forms (figs. 13 and 14, 

 ob.). But in these cases another feature, the shortening of 

 the pelvis, must be kept in view, and it is by no means 

 certain that there is a definite relation between the chanaes 

 of size of the bone and the muscle. There is some evidence 

 that the pelvis is becoming shorter in the more specialized 

 Kingfishers, and unless the muscle is shortened at precisely 

 the same rate, a shortened pelvis would conceal a simultaneous 

 shortening of the mnscle. This raises the very large and 

 important question of the independence of the "growth 

 forces,^' which in some cases seem to be displayed by 

 different parts of an organism, while in other cases alteration 

 in parts seems to be accompanied by a recovery of the 

 original symmetry. I do not think that there is at present 

 enough material for the discussion of this subject. 



Pub-ischio-feinorales {adductors) . — Ceryle maxima (fig. 13, 

 add. 1, add. 2) and C. inda (fig. 14, add.) show two condi- 

 tions. In C maxima the superior adductor is much smaller 

 and distinct, having no connection with the gastrocnemius, 

 while the internus is fused along a diagonal seam with the 



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