63.6. DR. p. CHALMERS MITCHELL ON THE [DeC. 17,. 



Alcedinidse, has some members with the wing in the diastataxic 

 condition and some members with the wing eutaxic, and there is 

 no direct relation between the distribution of these conditions and 

 the accepted classifications. On the assumption that eutaxy is an 

 apocentric modification of the archecentric diastataxy, it is plain 

 that it must be what I term a multiradial apocentricity, a condition 

 that has been produced several times independently. How far is 

 this apocentricity found associated with other apocentricities ? In. 

 the wing-feathering generally there is an association between 

 eutaxy and the degeneration of the carpal remex. Bhinochetus is 

 the only eutaxic form in which the degeneration of this feather 

 has not been carried far; Eurypyga is the only form of those 

 that I have examined in which diastataxy is associated with a 

 great degeneration of the carpal remex. 



The G-ijt-Patterns. 



I have recently (10) described and discussed the patterns dis-; 

 played by the convolutions of the Intestinal Tract among the 

 Gruiformes. They are all modifications of a metacentral condition 

 closely resembling that found underlying the modifications of the 

 Charadriiformes. It is enough to say here that Aramus appears 

 to show the most primitive condition in the group, a condition in 

 which there is little trace of the special Ealline pattern. The. 

 Ealliue pattern is very definite, and the patterns found in the 

 G-ruiuffi, Psophiinae, and Heliornithidse are practically identical with 

 it, Bhinochetus, Dicholophus, and Otis show apocentric modifications 

 of the Ealliue type. Eurypyga stands out from the others, 

 showing, in this respect, only an extremely generalized relationship 

 with the group. _ _ ■ 



The divergence of patterns among the Gruiformes is certainly 

 not great, but none the less is in striking contrast with the 

 practically complete identity of pattern found among the different 

 members of the Columbidse or of the Alcedinidse, the state of 

 affairs pointing out that the Gruiform assemblage is far from 

 coherent. Aramus and Eu,rypyga, two diastataxic forms, display 

 the most archecentric patterns found in the group; the other&, 

 eutaxic or diastataxic, are all apocentric, that is to say are far 

 modified from the Avian archecentric condition. ; . 



MtrscuLAE Anatomy. 



Latissimus clorsi anterior et posterior. — The conditions of these 

 muscles present a considerable range of variation among the 

 Gruiformes. ■■. . ;: 



In the Eallidse (when I use family names in this memoir I mean to 

 imply only those examples mentioned as having been dissected) both 

 divisions "of the muscle are large and unusually strong, with a wide 

 origin from the dorsal vertebral spines extending from the posterior 

 cervicals to the ihum. The posterior margin of the anterior 

 division is . in contact with the anterior margin of the posterior 



