124 MR. SCLATER ON THE AMERICAN CATRIMULGID.E. [Feb. 27, 



as regards the number of the phalanges of the digits in the class of 

 Birds — the fourth or outer toe having only four phalanges, like the 

 third or middle one. This peculiarity is accompanied by the pre- 

 sence of the well-known pectination of the inner edge of the claw of 

 the long middle toe. This structure of the feet is met with in all 

 the typical Caprimulgidce — that is, in all the forms allied to our com- 

 mon Caprimulgus europaus. (See figs. 1, 2.) 



Fig. 2. Fig. 1. 



Fig. 1. Left foot of Anfrostomus vociferus. 

 2. Left foot of Ni/ctidromus albicollis. 



In the second division, containing the genera Steatornis and Nijc- 

 tibius of the New World and Podargus, Batrachostomus, and JEgo- 

 theles of the Old World, the pectination of the medial claw is want- 

 ing, and the outer digit has the normal number of fire phalanges. 

 (See figs. 3, 4, and 5.) 



A second part of the skeleton of the Caprimulgidce, which presents 

 us with some very important characters, is the sternum. The great 

 differences between the sterna of Caprimulgus and Podargus have 

 been well pointed out by M. Blanchard*, and may be seen at a glance 

 on reference to the two sterna of Caprimulgus stictomus, Swinhoe, 

 and Podargus plumiferus, Gould, which I now exhibit. (See figs, (i 

 and 8.) They are such as scarcely occur in any other natural family 

 of birds, and may probably ultimately necessitate the separation of 

 the forms allied to Podargus into a distinct family f. Of the sternum 



* Osteologie des Oiseaux, p. 94. 



t Dr. Cabanis has proposed (Orn. Not. in Wiegm. Arch. 1847, p. 343) to re- 

 move the Podargincs into the family CoraciidcB, but without giving any very good 

 reason for so doing. At the same time, he leaves Nyctibius with the Caprimul- 

 gidce. Dr. Cabanis considers that the Podargincs are most nearly allied to the 

 Eurylcsminm, which, however (except Pcltops, which is a Muscicapine form allied 

 to Monarcha), I agree with Mr. Wallace in placing next to the American C'o- 

 tingidm. It seems to me that wherever Podargus and its allies go Nyctibius 



