152 MR. F. E. BEDDARD ON THE SYRINX AND OTHER [Mat. 2, 



and anterior air-sacs ; towards the median line, however, its limiting 

 septa coalesce, and here the anterior and posterior intermediate air- 

 sacs follow each other directly; this supplementary air-sac therefore 

 is placed upon the outer margin of the lung and does not extend to 

 the middle hne. The other specimen of Steatornis unfortunately had 

 the lungs destroyed, so that I cannot positively state whether the 

 above-described peculiarity is merely a variation or characteristic of 

 the bird, though on one side there were certainly two ostia to the 

 posterior intermediate sac. 



Myology. 



The disposition of the tensores patagii varies characteristically in 

 the different genera. In Caprimulgus, Nyctidromus, and Chordeiles 

 there is a biceps-slip, which is absent in Steatornis, Podargus, and 

 Mgotheles. Prof. Garrod has figured the patagial muscles of Steat- 

 ornis {lac. cit.), and I find tliem to be exactly similar in Podargus. 

 ^gotheles is a little different from either of these genera ; tliere is no 

 anterior branch to the tendon, or only just a trace of one, close to the 

 insertion on to the extensor muscle. In Caprimulgus, Chordeiles, 

 and Nyctidromus there is an absolute similarity in respect of lliese 

 muscles ; since Caprimulgus has been already figured by Grarrod 

 (loc. cit. p. 185), there is no necessity to illustrate the two remaining 

 genera, as it would be merely a repetition of his figure. 



A peculiarity in the myology of Steatornis is not referred to by 

 Prof. Garrod in his account of the anatomy ol' that species ; that is 

 the presence of an ewpansor secundariorum. In a later paper, where 

 a hst is given of those families that are characterized by having an 

 expansor secundariorum muscle, he states that the Coraciidaj are the 

 only Anomalogonatous birds which are thus provided. In the speci- 

 men of Steatornis before me there is a well-developed expansor 

 secundariorum arising in the usual way and attached to the teres 

 near to its insertion. The termination of the exjiansor secundariorum 

 in Steatornis is therefore similar to that which has been recorded by 

 Garrod in Ortyx, Numida, &c. Since noting this fact I see that 

 Mr. Forbes ' has already mentioned it. 



The biceps muscle is split about halfway down into two distinct 

 tendons of insertion, which are severally attached to the radius 

 and ulna. In Podargm, JUgotheles, and Nyctidromus the biceps is 

 similarly divided into two, the division passing for a certain distance 

 into the substance of the muscle itself, and not being merely restricted 

 to its tendon of attachment. This structural feature is not peculiar 

 to the Caprimulgidse, but is found in other families of birds. 



In all the Caprimulgidse that I have dissected, the anconeus longus 

 has a tendinous humeral head. 



The peroneal muscles vary in the different genera of Caprimulgidse : 

 in Steatornis and ^gotheles only the peroneus brevis is present ; 

 in Podargus both peroneals are present with tlie usual attachments ; 

 in Nyctidromus I could only find the peroneus longus. 



' Coll. Papers, p. 346. 



