176 Proceedings of the Biological Society of Washington . 



the gall bladder (Fig. 4, gr) is found in the 

 usual position above it in contact with the 

 anterior end of the small intestine and the 

 adjacent side of the stomach. It lies ex- 

 ternally to the median line of the lobe. Seen 

 from above when fully distended this cyst is 

 elliptical. In outline from the side it ap- 

 pears somewhat triangular with rounded 

 angles. This triangular appearance is in- 

 tensified in alcoholic specimens. In several 

 examined the posterior portion, nearly empty 

 Fif"'- 4- of bile, projects from the main body of the 



Viscera in Chordnlr.s ^ , -r 



viriiininmis with right cyst as an elongate sac. in one specimen 



lobe of liver raised to .' ^wor.\ ,i n i i t i 



show position of gall (A. W . No. 2/83) the gall bladder measures 



bladder. (/. prall bladder; , ■, n ^ i r. >- • i 



d. f-ysio-enteric duct approximately 7 mm. iong by d.O mm . Wide. 



(about life size). „, , , . t , /-r^- a t\ • 



The cysto-entenc duct (.rig. 4, a) rises near 

 the center of the sac on its external side and passes back to empty 

 into the ascending arm of the duodenum near its summit. 



Through the courtesy of Dr. C. W. Richmond, Acting Curator 

 of Birds in the United States National Museum, I have been 

 able to examine three alcoholic specimens of Chonleiles uc%di- 

 pennis (U. S. N. M. Nos. 17,487, 17,488 and 18,791) in the 

 Division of Birds. In each of these a gall bladder, identical 

 in position and form with that above descril)ed in C. virginianus 

 was found. In No. 17,487 this cyst measured 6.8 mm. long 

 by 3.4 mm. in vertical diameter. In the other two specimens 

 the sac was less perfectly preserved. In these specimens the 

 cysto-enteric duct had the same point of origin and emptied 

 into the same portion of the duodenum as in Chordeiles virgini- 

 anus. 



In the preparation of this paper no attempt has been made 

 to distinguish subspecies among the nighthawks, as the work 

 was done entirely with alcoholic specimens, difficult to deter- 

 mine other than specifically. In the drawing (Fig. 4), made 

 from Chordeiles virginianus, the points illustrated are necessai-iJy 

 made somewhat diagrammatic. The right lobe of tlie liver has 

 been raised to show the gall bladder and the upper portion of 

 the pancreas removed to uncover the cysto-enteric duct. Tlie 

 point of origin of this duct is hidden, as is also the place at 

 which it empties into the intestine. 



