Viperidce. 



rROCODILTANS, LIZARDS, AND SNAKES. 699 



Hydrophida'. 



I. One lung and no rudiment, continuous witli tracheal lung, which extends to 

 head. 



Sydrophis hardwickii Gray (a slight constriction between tracheal and posttracheal 

 lungs) ; H. ellioiii Giinther. ; Hydrus hicolor Daudin. 



II. A rudimental right lung connected with the left lung, which is separate from 

 the large tracheal lung. 



Platurits latirandatus Linn;eus. 



SOLENOGLTPHA. 



A tracheal lung, continuous with the normal lung. 



Cauaidce. 

 No rudimental lung. 

 Causiis rhomheatus Lichtenstein. 



No rudimental lung. 

 Dendraspis polylepis Giinther. 



No rudimental lung. 

 Clotho arietans Linnfeus. 



Crotalid(r. 



I. No rudimental lung. 



Bothrops lanceolatiis Linnteus; Ancistrodon piscirorus Lac^pfede; Sistrurus catenafus 

 Ratinesque; Crotalua adamanteus Beauvois; C.confluentus Say. 



II. With a rudimental right lung. 



Bothrops pictas Tschudi; JS. erythriirus Cantor; Telenraspis schlegelii Berthold; 

 Ancistrodon contortrix Linnaeus; Crotalus horridus Linnteus. 



The rudimental lung is often concealed from Tiew and difficult to discover. The 

 best test of its presence is the foramen which connects it with the trachea, which 

 will generally be found piercing the cartilage of the latter near the apex of the 

 heart. The rudimental organ may then be found by inserting a bristle, and observ- 

 ing 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 tirst ascertained, and a longitudinal median incision 

 made in the abdominal wall. In all forms except the Epauodonta 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 turn- 

 ing the free margin upward as the snake lies on its back, the foramen hroncliiale will 

 be seen, and its lumen can be explored. The trachea is concealed by the o'sophagus, 

 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 toward the head. 



THE UROGENITAL SYSTEM. 



The Serpen tes possess no urinary bladder, but the ureters empty by 

 separate orifices into the cloaca. The kidneys are unsymiuetrically 

 placed, that of the right side being anterior to that of the left. They 

 are transversely lobate. The testes and ovaries are situated consider- 

 ably anterior to the kidneys, and are similarly unsymmetrically placed, 

 that of the right side being anterior to that of the left. The vas deferens 

 is closely folded in its proximal portion, and runs along the external 

 side of the kidney, where it is accompanied by the ureter. The two 



