284 THE ARCTURUS ADVENTURE 



up to the well in the boat. He was one of about 

 seven or eight hundred which were so busy graz- 

 ing that they paid no attention to the abstraction 

 of their comrade. These blue cows, as we called 

 them, are fish from a foot to eighteen inches, weigh- 

 ing from one to four pounds, and are by far the 

 most abundant of this medium-sized class. Their 

 body is very deep and compressed, like most of 

 the surgeonfishes, and their thick, pouting lips 

 and protuberant eyes make them look absurdly like 

 some stout people I see from time to time. 



Ninety years ago the French frigate Venus 

 paid a visit to the Galapagos Islands and a speci- 

 men of these yellow-tails was collected. To this 

 specimen Valenciennes gave the name Piionurus 

 laticlaviiis , but the exigencies of priority demanded 

 a shift and today it is known as Xesurus laticlav- 

 ius. It is an appropriate title and freely trans- 

 lated means the Side-striped Scraping Tail. 

 Using Tail as a proper name is excellent in this 

 case, for of everything about the fish the tail is 

 the part most conspicuous ( Plate VI ) . 



They are a uniform slaty -blue in color with two 

 broad bands of black which extend downward 

 across the body, one beginning on the neck and 

 curving downward through the eye to the mouth, 

 and the other just behind, starting at the front 

 of the dorsal fin and ending at or below the pec- 

 toral. The tail is bright greenish yellow, and a 

 streak of this color reaches forward beyond the 

 base, outlining, on the sides, the three poisonous, 

 file-like spines. 



