1886.] POINTS IN THE ANATOMY OF THE CAPRIMULGID^. 153 



Dr. Gadow, in Bronn's 'Thierreichs ' (Bd. vi. Abth. iv. p. 177), has 

 referred to the double condition of the tendon of the tibialis anticus 

 in Podargus ; this statement I am able to confirm from my own dis- 

 section of that bird ; but in the other genera this muscle has a more 

 normal arrangement, being undivided at its extremity. The only other 

 birds in which I have found a similar disposition of the tibialis 

 anticus are the Owls (Strix pratincola); but Dr. Gadow has men- 

 tioned Chrysotis as another instance. 



Steatornis differs from the other genera in having no femoro- 

 caudal muscle ; in the remaining genera the formula on Garrod's 

 system is AXY\ 



Steatornis therefore agrees with Podargus and JEgotheles in the 

 absence of a biceps slip to the patagium ; while those genera which 

 agree with each other in the possession of a tracheo-bronchial syrinx, 

 viz. Gaprimulgus, Nyctidromus, and Chordeiles, have a biceps slip ; 

 Steatornis is peculiar in the absence of the femoro-caudal muscle, 

 and in the presence of an expansor secundariorum ; while Mgo- 

 theles appears to differ from its allies in having no caeca, and also 

 in the structure of the patagial tendons. 



I am unfortunately uuable to give any account of the visceral 

 anatomy and myology of Batrachostomus, which I should imagine 

 will be found to agree pretty closely with Podargus. 



All these facts lend additional confirmation to the generally 

 accepted view that Steatornis is a peculiar type of Goatsucker and 

 needs a special subfamily to itself. It evidently, however, comes 

 nearest to Podargus, Batrachostomus, and JEgotheles ; and the fact 

 that all these genera lay white eggs'' is so far confirmatory of the 

 anatomical resemblances : in the other Goatsuckers the eggs are 

 coloured. A second subfamily will include Podargus and Batracho- 

 stomus, while ^gotheles ought perhaps to be regarded as the type 

 of a third subfamily. The remaining genera, Caprimulgus, Chor- 

 deiles, and Nyctidromus, belong to the fourth subfamily. 



The Steatornithinse are at one extrenie, and the Caprimulginse at 

 the other ; Podargus, Batrachostomus, and ^gotheles are much 

 nearer to Steatornis than to Caprimulgus, but should be placed in 

 an intermediate position. 



This view of the affinities of the different genera of Caprimulgidse 

 almost entirely bears out the scheme of classification proposed by 

 Mr. Sclater (loc. cit.). 



' Coll. Papers, p. 346. 



2 Cf. P. L. Sclater, P. Z. S. 1866, p. 127. 



Proc. Zool. Soc— 1886, No. XI. 11 



