THE ABALONES OF CALIFORNIA 



537 



anteriorly to the side of the head, there turns on itself and proceeds 

 back to the stomach, where it again goes forward, passing through the 

 ventricle of the heart, to terminate in the anus, which opens into the 

 gill cavity. The shell is perforated, toward the left, by a series uf 

 openings lying above a slit in the mantle fold leading into the gill 

 cavity, whence issues a stream bearing the excrement, respiratory 

 and excretory wastes. Three tentacular processes from the edges of 



Feeding Abalones from the Hand, a, h, grasping kelp with anterior processes of 

 foot ; c, drawing kelp under foot ; d, eating hole in kelp. 



the mantle cleft project through these holes. As the animal grows the 

 apertures in the shell behind the respiratory cavity are closed up and 

 new ones are formed at the anterior edge. 



The head terminates in a short snout on either side of which is a 

 somewhat slender olfactory tentacle and slightly lateral to this a shorter 

 and broader optic tentacle. Two elongated ganglia lying above the 

 mouth cavity may be called the brain because they form the center for 

 nerves from the eyes, olfactory tentacles, snout, lips and other parts of 

 the head. The eye is a simple cup-shaped depression of the epithelium 

 on the end of the tentacle. The cup is filled with a gelatinous lens and 

 it has clear and pigmented retinal cells connected with fibrils from the 



VOL. LXXXIT.— 37. 



