CONUS ARTERIOSUS IN TARPON ATLANTICUS. 



mm., the shortest measures 11 mm., and is transverse. The 

 conus wall is slightly under 2 mm. in thickness. The total 

 length of the conus varies according to the site of measurement, 

 at the mid-dorsal and mid-ventral lines it measures 8 mm., 

 laterally its measurement increases, until at the mid-lateral line 

 on either side it becomes 10 mm. 



FIG. I. The heart has been opened by a mid-ventral sagittal incision, and the 

 parts widely separated (natural size). A, aorta; A V, atrio- ventricular valve; B, 

 bulbus arteriosus ; C, conus arteriosus ; D, left distal conus valve ; P, r 'ght proximal 

 conus valve ; V, wall of ventricle. 



In order to compare the relative lengths of conus and ventricle 

 in Tarpon and Amia, the length of the ventricle has been meas- 

 ured by plunging a needle into the apex of the ventricle, in such 

 a direction that its point emerges where the ventricle and conus 



