OP THE CETACEA. 53 



nate posteriorly in a common pouch or bag, called 

 the pharynx, from which both the windpipe and 

 gullet take their origin ; the former, and anterior, 

 through an aperture called the glottis, which is 

 covered by the epiglottis as a valve, which usually 

 stands erect, but upon the passing of a morsel, shuts 

 down like a lid, and so leaves a free passage for 

 the food. In the Cetacea the spiracles admit free 

 ingress and egress of air into and from the lungs ; 

 but as the mouth is at the same time usually filled 

 with water, some mechanism must be provided to 

 prevent it from rushing into these organs. The 

 peculiarity then commences at this point. The 

 epiglottis, instead of being a simple and usually 

 unshut lid, forms in some of the Cetacea the anterior 

 rim of the rima or slit, and in others encloses these 

 parts at their base, and assists them in forming a 

 projecting tube or canal. In this particular there 

 is great variety in the individual species ; and, as a 

 sample merely, we refer to sketches i and &, which 

 exhibit the larynx in the common dolphin as 

 sketched in the Encyclop. Methodique, and in the sea 

 unicorn, as represented by Dr. Fleming ; in both of 

 which it will be seen that the rima glottidis is on 

 the summit of a projecting cone or pyramid. This 

 is received into the lower end of the blowing-tofo, 

 which is a circular aperture, surrounded with a 

 strong sphincter muscle which includes the glottis 

 in its grasp, thus uniting the windpipe and the 

 blow-tube, which cross the fauces or swallow, and 

 divide it into two passages. In some of the species 



