74 Sclater on the Systema Avium. 



be better for the future to restrict the term Coccyges to these two 

 families. The question then is. what shall we do with the re- 

 maining groups of the order ? The arrangement of them by the 

 structure of the feet, according to Prof. Huxley's scheme, al- 

 though very simple, is not quite natural. Leptoso?tia* for instance 

 (as I believe I first showed in 1865*), although the outer toe is 

 more or less reversed, must certainly come near the Rollers 

 (Coraciidae) ; and Co/?Wwould now appear to be nearly related to 

 the same group,| although its foot-structure is by no means sim- 

 ilar. There seem in fact to be several different categories com- 

 bined in the order Coccyges thus considered. First we have the 

 Lipoglossas of Nitzsch. consisting of the four families Alcedinidae, 

 Bucerotidag. Upupidae, and Irrisorida?. \ These all belong to the 

 Piciformes of Garrod. § and all the best authorities are pretty 

 well agreed as to their consanguinity. Along with these must 

 come the Cuculinae calopterae or Todidae of Nitzsch. containing 

 also four families, which, to my mind, are also closely related — 

 namely the Meropidse, Coraciidae, Momotidas, and Todidae. The 

 two last-named groups are united by Garrod into one family. || 

 Thev all four have twelve tail-feathers, a naked oil-gland, and 

 caeca. But to these must be added, as aberrant appendages 

 (which sadlv mar the uniformity of the group), the Leptosomidai 

 and Podargidoe and, as it would appear from Prof. Garrod's re- 

 searches, the Coliida?. Leptosoma. as stated above, is clearly 

 more allied to the Rollers than to any other form. Padargus 

 cannot be left with the Caprimulgidae. looking to the conformation 

 of its palatal bones,^[ and comes in best here, whereas Nvctibius 

 belongs truly to the Caprimulgidae.ft After Garrod's exhaustive 

 disquisition on Steatornis*%% we can no longer complain that its 

 structure is unknown ; but it becomes still more difficult, owing 

 to its numerous peculiarities, to arrange this most extraordinaiy 

 bird in a satisfactory place in the series. It must certainly be 

 either put in here or placed as a separate order next to the Striges. 

 Perhaps the former plan is for the present the most convenient. 



* P. Z. S. 1865, p. 682. Mr. Sharpe, in making the Leptosominae merely a subfamily 

 of Coraciidte (Ibis, i8yi,p. 285), appears to have entirely overlooked the structui* of 

 the feet. 



t Cf. Garrod, P. Z. S. 1876, p. 416. 11 Huxley, P. Z, S. 1867, p. 445. 



+ Pterylography, p. 102. ft Huxley, /. c. p. 454. 



§ P. Z. S. 1874, p. 117. $$ P. Z. S. 1873. p. 526. 



|| See P. Z. S. 1S70, p. 101. 



