1G2 



AMERICAN BITTERN. 



narrow .ibove, and on the upper margin bocoine o jnsiderably thickened and send oft" a spur, the occipitil 

 vocal, on either side, which adhering to the crest of the bone of the back of the skull, above all of the neck 

 inusc'les, act as retractors. These occipitals are .20 wide by some 2.CX) long, but are thin. See fig. 32, c, c, 



Fig. ;VJ. Upper portion of head of American Bittern, one half life sz!, b, b:ll 

 muscle ; o, thoracic ; r, tendons, s, vertebral muscles. 



r r 



c, ocjipital vocal 



where I have represented the upper side of a Bittern's head, one half life size, and fig. 33, where a side 

 of the same is ''iven, s, being the upper portion of the compressing muscle. Also see fig. 34 where an 



view 



ideal section of a pumping Bittern is given, the lettering being the same as above. 



On the lower margin of each enveloping muscle, near the base of the neck, is a narrow spur or rather a 

 prolongation of the muscle, .50 wide by 2.0) long, but thin. Fig. 34, t. This is attached to the muscles in 

 the scapular regions, and sends a branch across the back to meet its fellow on the opposite side. 



On the lower portion of the upper margin of each envelojiing muscle, .another spur arises, which 

 proceeding upward, adheres to the lower portion of the bill, directly beneath the nostrils, fig. 33, p o, and fig. 

 34, p. This is also a retractor and supporting muscle. 



Fig. 33. Side view of head of American Bittern, one half life size ; b, bill ; n, nostril ; a, eye ; 

 c, occipital vocal ; o. thoracic : r, tendons ; s, oesopliagul muscle ; p, maxillary vocal muscle. D, 

 external closing valve of nostril. 



These three accessory muscles support the enveloping muscle and aid in contracting it. Another 

 function of the scapular attachment is to act as a kind of a spincter, to cut oft" the air in the gullet ami prevent 

 it from entering the proventriculus and .stomach. The function of all the muscles thus fiir mentioned, is to 

 force the enclosed air out of the expanded gullet. 



For retaming the enclosed air in the gullet, there is a most singular arrangement. Lying on either 

 side of the neck, attached partly to the first and partly to the second neck joints, is a short, thick, 

 muscle, the thoracic, to the lower side of which is attached the occipital. See figs. 32, 33, and M, o. This 

 peculiar muscle is l."20 long, .itOwide and .45 thick. It arises well under the neck, and when swollen by 

 contraction, bulges out and meets its fellow opposite, and these, with the upper larynx, which lies beneath 

 thep\and a little behind, but which can be firmly pressed against them, completely obstruct the passage to 



