cope.] 224 [May 18, 



the trachea, which will generally be found piercing the cartilage of the lat- 

 ter near the apex of the heart. The rudimental organ may then be found 

 by inserting a bristle, and observing its destination through the more or 

 less transparent tissues. In but one instance have I found a rudimental 

 lung without a connecting foramen, viz., in the Mexican Ficimia olivacea. 

 On the other hand, the foramen may terminate in a small blind sac. 



The pulmonary characters may be determined without much dissection. 

 The position of the heart must be first ascertained, and a longitudinal 

 median incision made in the abdominal wall. In all forms except the 

 Epanodonta and Catodonta, the trachea will be found passing to the left 

 side of the heart, and entering the lung near its apex. By splitting the 

 trachea, not too near its abdominal border, on turning the free margin 

 upwards as the snake lies on its back, the foramen bronchiale will be seen 

 and its lumen can be explored. The trachea is concealed by the (esopha- 

 gus, which must be drawn to the left side of the body in order to make the 

 examination. The examination of the tracheal lung requires the division 

 of the abdominal wall further towards the head. 



EXPLANATION OF PLATES. 



The figures variously reduced ; the heart and liver are turned over to 

 show the trachea and lungs. 



Plate XL 



Typhlops Uberiensis Hallow. 



Plate XII. 



Charina bottie Blv. 



Plate XIII. 

 Ghemydrus (jramdatus Merr. 



Plate XIV. 

 Coluber quadrmttatus Holbr. 



Plate XV. 

 Heterodon platyrMnus Latr. 



Plate XVL 



Crotalus confluenius Say. 



Lettering. 



(E, (Esophagus; St., Stomach; I., Intestine; R., Rectum; C, Co?- 

 cum ; 2'r., Trachea ; H. L., Right lung ; L. L., Left lung ; T. L. Tracheal 

 lung; B. F., Bronchial foramen; L., Liver; Q., Gall bladder; K, 

 Kidney; f/.. Ureter; 7'., Testis ; F. i?., Vas deferens ; Oy., Ovary ; Od., 

 Oviduct; V., Vagina; i'^., Fontanelle ; C. A., Corpus adiposum ; 7/., 

 Heart ; A. R., Aorta root; Ca.t., Carotid ; J., Juglar vein ; V. C, Vina 

 cavi. 



