368 NATURAL HISTORY OF BIRDS. 



ORDER XVII. PICARIAE. 



Coinciding with Professor Newton's words, that the Picariae " are already a suffi- 

 ciently heterogeneous assemblage " to also include the owls, we retained the latter 

 at the end of the Raptores, though admitting that this group, thereby, becomes 

 even more heterogeneous than the Picarians. But, true to our principle of not 

 exchanging one doubtful course for another equally doubtful, we think it safer to 

 adhere to the arrangement adopted. That we have here indicated the true course of 

 development of some of the Picariae at least, the goatsuckers and their allies, 

 seems, however, less doubtful. Another line of descent seems to connect certain 

 forms included in the present order with the Gallinaceous birds, through the Muso- 

 phagidae. If this view be correct, then the ' order ' Picariae will have to be split up 

 according to its double descent. 



To the scientific ornithologist, the Picariae form an assemblage of the greatest 

 interest. Their anatomy has in many instances been worked up pretty well, and has 

 disclosed a multitude of characters, generalized as well as specialized, extremely 

 marked, but pointing in all directions. Numerous classificatory attempts have been 

 made, based upon the most different principles, and the most varied sets of characters ; 

 still, whether based upon external or internal structure, the general aspects of these 

 different systems show greater similarity than might be expected. Messrs. Garrod 

 and Forbes have especially elucidated the anatomy of the Picarians, and their opin- 

 ions are, therefore, entitled to special consideration. A brief summary of the more 

 important structural features of the different groups is therefore necessary, the more 

 so since we are obliged to dissent from some of the conclusions of these gentlemen. 



Mr. Garrod divided the forms here included into two main divisions, the Homal- 

 ogonatae, which possess the ambiens muscle, and the Anomalogonataa, which do not 

 have it. The former, viz. the Cuculidae and Musophagidae, he referred simply as 

 families to the ' order ' Galliformes, while of the latter, plus the Passeres, he made an 

 'order' under the above name. This order he again subdivided in Piciformes, Passer- 

 iformes, and Cypseliformes. The last mentioned group is generally admitted to be 

 natural and distinct ; the other two, and the removal of the Coccygiformes, are rather 

 novel features, and need explanation. 



The Cuculidae and Musophagidae are zygodactylous, i.e., they have two toes in 

 front and two behind, like the woodpeckers and allied forms, with which they have 

 usually been placed. The structure of the foot is so characteristic that more than the 

 presence of the ambiens muscle would be required to remove them from that neigh- 

 borhood. Such additional features are also found in the skeleton, as well as in the 

 myology and pterylography. Not to go too deep into details, we shall only refer to 

 the arrangement of the muscles that bend the toes, viz. the deep plantar tendons. In 

 the introduction (page 14), mention is made of the fact that in the Cuculidae and 

 Musophagidae the flexor perforans splits up to supply second, third, and fourth digits 

 or toes, i. e. to the three toes which in most other birds are directed forwards, while 

 the flexor hallucis is single, and only goes to the hallux ; this arrangement is the origi- 

 nal one, as it seems, and the commonest amongst the birds, hence we call it nomopel- 

 mous; in the cuckoos, parrots, gallinaceous birds, the two tendons are united at their 

 crossing point by a vinculum ; these are therefore called desmopelmous, while the 



