OAPRIMULGI 243 



the skull is desmognathous, the syrinx is bronchial (least 

 marked in Mgotheles), and the outer toe has five phalanges, 

 while the middle toe has no serration. This is a fair 

 assemblage of identical characters. It is usual for Steatornis 

 to be separated as a distinct family from the Podargidse, as 

 has been done by Gadow. It differs from Podargus in 

 seven out of the thirteen characters made use of in the 

 above table. It is often supposed that the Guacharo is 

 peculiar among goatsuckers by reason of its vegetable diet ; 

 but Newton states in his ' Dictionary of Birds ' that the 

 Podargidse also partlj^ nourish themselves on fruit. More- 

 over Mgotheles, which is by universal consent placed in the 

 immediate neighbourhood of Podargus, differs from that 

 genus in four out of the thirteen characters, and from Stea- 

 tornis in exactly the same number. It appears possible to 

 place all these genera in one family, which, on account of its 

 greater antiquity, has had time to vary more than the Capri- 

 mulgidse. It is also among members of this family that the 

 greatest number of points of affinity to the owls is met with, 

 a further argument in favour of their basal position. 



The relationship of the Caprimulgi to other groups is a 

 puzzle hard of solution. This is partly, perhaps, due to the 

 fact that the goatsuckers are probably a somewhat ancient 

 group. That they are an ancient group seems to be shown 

 by the considerable amount of specialisation of structure 

 which they exhibit, by the primitive character of the 

 intestinal folds — the caeca being at the same time well 

 developed — by the double carotids, and by their wide distri- 

 bution, with a restriction in range of some peculiar types, 

 such as Steatornis. 



The remarkable series of modifications of the syrinx is 

 one of the most striking facts in the anatomy of the group. 

 They share this with the Caculi, and, though to a less extent, 

 with the Striges. It is, indeed, with this latter group that 

 the goatsuckers seem to be most nearly allied. This con- 

 clusion, which is in harmony with much recent opinion, is 

 curious in view of the external likenesses ' which bind 



' For instance, the ' ears ' of certain Podargidse and of Lyncotnis. It is a 



R 2 



