1917.] Lang and Chapin, Field Notes on African Chiroptera. 505 



Hypsignathus monstrosus was also heard and seen by us as far up the 

 Ituri as Penge, and on the River Epulu, while at Stanleyville from August 

 to December this call was not infrequently noted, but that of Epomops 

 franqueti was the more usual. The species ranges, however, from Lake 

 Victoria (Andersen), through the upper Ituri, northward to Niangara (in the 

 Uele), and westward across the forested portions of the Congo basin and 

 the Kamerun (Bates & Sjostedt), along the Gulf of Guinea to the Gambia 

 (Biittikofer). It shows a great liking for the neighborhood of water. 



The pharynx, larynx, and hyoid bones of various species of Epomo- 

 phorus and Epomops, as well as of Hypsignathus monstrosus, were carefully 

 studied by Dobson. 1 The last-named species, however, he dismissed with 

 a few words: "There are no posterior air-sacs; but the anterior sacs are 

 well developed, and separated internally below, not by a thin partition as 

 in the above-named species [i. e., of Epomops], but by an intermediate sac 

 communicating with the pharynx by an aperture between the mylo-hyoid 

 tendons." Matschie, in 1899, 2 remarked briefly upon the enormous size 

 of the larynx in the male of Hypsignathus, and gave a figure illustrating it. 



The results of our two dissections are embodied in figures 19 and 20, 

 where the proportions and structure of the larynx, as well as the arrange- 

 ment of the remaining viscera, are clearly shown. The soft palate is 

 greatly prolonged and divides the pharynx into two separate parts, a large 

 thin-walled nasopharynx and a narrow, thick-walled oropharynx. The 

 lumen of the oropharynx, like that of the esophagus, is so small as to indi- 

 cate that only the juices of fruits are swallowed. 



Into the sides of the nasopharynx open the pair of air-sacs, which lie 

 in front of the sterno-mastoid muscles and just below the parotid glands. 

 We were unable to find, in either of our specimens, the second pair of sacs 

 mentioned by Matschie as lying near the shoulder; and there is no median 

 ventral sac as described by Dobson. A tearing of the muscles of the throat 

 in one specimen, due to the stretching of its neck after preservation in 

 alcohol, at first deceived us, but the cavity we mistook for an air-sac proved 

 to be simply a rent in the areolar tissue of the neck. 



The two lateral sacs, according to Prof. H. v. W. Schulte, are perhaps 

 to be looked upon, morphologically, as hypertrophied developments of 

 entodermal pharyngeal pouches — probably the third or fourth pair — 

 and equivalent to the occasional internal branchiogenetic sacs of the human 

 embryo. 



In no other mammal is everything so entirely subordinated to the organs 



1 Proc. Zool. Soc. London, 1881, pp. 685-693. 



2 Sitzber. Gesell. Naturfor. Fr. Berlin, 1899, p. 28. 



