THE ARTERIES 151 



rows behind, the number increasing to five or more 

 in front. Parallel to these runs a row of very 

 minute setse on the inner side. 

 c. The auditory nerve supplying these rows of setse 

 may have been removed with the muscles, but 

 should be looked for. 



3. Olfactory setse. On the ventral surface of each joint of 

 the exopodite of the antennule are two tufts of fine 

 sensory setse. Under a low power of the microscope 

 each is seen to consist of two joints, of which the 

 distal one is much the longer, and is flattened. They 

 are probably olfactory in function. 



III. THE ARTERIES AS SEEN IN AN INJECTED SPECIMEN. 



Inject from the ventricle with water coloured with carmine. 



Kill the animal by dropping it into boiling water. Dissect 

 from the left side, removing the left half or more of the cara- 

 pace, and such parts of the liver, genital gland and duct, and 

 of the side-wall and muscles of the abdomen as may be neces- 

 sary to expose the following arteries. 



1. The ophthalmic artery is a median artery arising from 



the anterior end of the heart and running for- 

 wards over the stomach, then curving downwards 

 in front of the stomach and dividing to supply the 

 eyes. 



2. The antennary arteries arise from the anterior end of 



the heart, one on each side of the ophthalmic artery. 

 Each runs forwards, outwards, and downwards over 

 the side of the stoniach, to which it sends a gastric 

 artery ; and then forwards to the anterior end of the 

 head, supplying the kidney, antenna, and anteimule, 

 and sending a branch to the rostrum. On its way 

 it gives off numerous small arteries to the muscle? 

 of the regions which it traverses. 



3. The hepatic arteries arise from the ventral surface of 



the heart near its anterior end, and supply the liver, 

 in which they are buried. 



