18/4.] MR. A. H. GARROD ON THE MUSCLES OF BIRDS. 119 



either the ambiens muscle is absent, or has a nude oil-gland in com- 

 bination with intestinal caeca, it is certain to be a homalogonatous bird. 

 That the formula^of the Musophagidce is A B. X Y, and the ambiens 

 is present, therefore more than counterbalance the exception presented 

 by the arrangement of their caeca and oil-glands. The same remarks 

 apply to the Cuculidce. The Cathurtidce possess the ambiens, which, 

 in conjunction with many other Ciconiine characters, leaves no doubt 

 about their position ; and the Psittaci cannot, from the presence of 

 an ambiens in some of them, be placed with the Anomalogonati, to 

 which they otherwise present many points of similarity. 



Excluding the Macrochires, which have a nude oil-gland and no 

 caeca, all the other anomalogonatous birds have either a nude oil- 

 gland and ea;ca, or a tufted oil-gland and no caeca ; and this definite 

 set of features makes it easy to divide them up into two main orders, 

 the Piciformes and the Pas'seriformes. 



Piciformes, Passeriformes, 



with tufted oil-gland and no caeca. with nude oil-gland and cseca. 



("ici. Pusseres. 



Capitonidcp.. Bucconidce (?). 



Ramphastidce. Trogonldce. 



Vpupida. MeropidcB. 



Bucerotidce. Caprimulgidce. 



AlcedinidtB. Sleatornithidce. 



f Coraciidce. 

 \ Momotidce. 



The position of the Macrochires is uncertain. In so far as the 

 mouth tends to get very broad it resembles some of the Passeriformes. 



As before remarked, none of the Anomalogonataj possess the 

 accessory femoro-caudal muscle. In them also the posterior margin 

 of the sternum is more perfectly formed than in the Homalogonatae. 

 Scansorial feet are found in both divisions ; but whilst those of the 

 Parrots and Cuckoos exhibit a similar arrangement of the tendons of 

 the toes, the Toucans, Woodpeckers, and Jacamars follow a quite 

 different type. 



All the birds which present the palatal characters expressed by 

 Prof. Huxley's term Schizognathous, and the nasal characters 

 expressed by my term Schizorhinal, are homalogonatous. All non- 

 struthious birds with a truncated vomer are anomalogonatous. 



As to what appear to me to be the main divisions of the homalo- 

 gonatous birds, the myology of the thigh does not give more than a 

 certain amount of assistance. In list I. it will be seen that large 

 brackets precede the names of the smaller divisions or families, sepa- 

 rating them into what to me are worthy of the dignity of orders. 

 From these it is evident that I would divide homologonatous birds' 

 into four orders, I. Galliformes. II. Anseriformes, III. Ciconiiformes, 

 and IV. Charadriiformes (Schizorhinae). These must be considered 

 separately. 



The Galliformes include all the birds in which there is any 

 approach in structure to the common Fowl. With the exception of 



