152 MR. F. E, BEDDARD ON THE SYRINX AND OTHER [ Mar. 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 line. 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 
4Egotheles. Prof. Garrod has figured the patagial muscles of Steat- 
ornis (loc. cit.), and I find them to be exactly similar in Podargus. 
Aigotheles is a little different from either of these genera; there 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 WVyctidromus there is an absolute similarity in respect of these 
muscles; since Caprimulgus has been already figured by Garrod 
(Joc. 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 of that species; that is 
the presence of an expansor secundariorum. In a later paper, where 
a list is given of those families that are characterized by having an 
expansor secundariorum muscle, he states that the Coractidee 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 ¢eres 
near to its insertion. The termination of the expansor secundariorum 
in Steatornis is therefore similar to that which has been recorded by 
Garrod in Ortyx, Numida, &e. Since noting this fact I see that 
Mr. Forbes’ has already mentioned it. 
The diceps muscle is split about halfway down into two distinct 
tendons of insertion, which are severally attached to the radius 
and ulna. In Podargus, Zgotheles, 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 Caprimulgidze, but is found in other families of birds. 
In all the Caprimulgidee that I have dissected, the anconeus longus 
has a tendinous humeral head. , 
The peroneal muscles vary in the different genera of Caprimulgide : 
in Steatornis and digotheles only the peroneus brevis is present ; 
in Podargus both peroneals are present with the usual attachments ; 
in Myctidromus 1 could only find the peroneus longus. 
' Coll. Papers, p. 346. 
