106' Mr. P. C. Mitchell on the 



it is the anterior division that tends to be reduced ; and this 

 reduction, incipient in some of the diastataxic forms, becomes 

 striking in eutaxic forms. Thus in the eutaxic Ceryle 

 americana and C inda, as compared with the diastataxic 

 C. maxima and C. alcyon, the anterior division is veiy thin 

 and weak; the posterior is enormous, broad, and strong, and 

 with a considerable forward extension of its oriiiin. In 

 Halcyon a simihir condition exists, less marked in H. rufa, 

 plain in H. pileata. In Ciltura it is plain ; in Alcedo ispida 

 the anterior division appears only as a {q^ fibres; in A. ben- 

 galensis, A. asiatica, and in Ceyx the anterior division ia 

 absent, while the posterior has become very strong. 



Latisshnus dorsi metapataijialis. — This slip was equally 

 developed in all. 



Rhomboideus superficialis and R. profundus. — In the King- 

 fishers the superficial muscle extends further forwards, the 

 deep muscle fuither postaxially, the two partially overlapping 

 in the middle. These characteristics are accentuated in all 

 the eutaxic forms. The deep muscle tends to be thicker at 

 its anterior and posterior margins. This progress towards 

 secondary cleavage is well advanced in Sauropalis vat/ans, 

 alone in this respect among the diastataxic forms, while in 

 the eutaxic FI. 7'ufa, the Ciltura, Ceryle americana, Ceyx, 

 and the Alcedines it is obvious. 



Supracoracoideus. — Markedly bipinnate in all and without 

 notable variations. 



Coraco-brachialis externus is in all a small fleshy muscle. 



Coraco-brachialis internus is in all a small muscle arisin<r 

 from the postero-lateral part of the coracoid, with a slight 

 overlap on to the sternum, and is inserted to the dorsal 

 surface of the median tubercle of the humerus. 



Biceps presents no marked differences, and the bleeps 

 patagialis is absent in all, as in the Passerines and other 

 birds called anomaloyonatous by Garrod. 



Alar Muscles. — The wing is the most distinctive part of 

 the Avian body, and the modifications in it deserve special 

 attention when the relative specialization of diff'erent birds is 

 being considered. The group of alar muscles and tendons 



