52 collector's manual 



solution to enter freely. It may be necessary in the case of fishes 

 that feed on vegetation to open the intestinal tract and remove 

 the accumulated vegetable matter. 



Fish too large for preservation in the containers available 

 should be skinned. Make a slit along the abdomen and remove 

 from beneath the skin the flesh from both sides of the body, but 

 leave all the fins in place. The head and tail should be left attached 

 to the skin. This skin can then be placed in formalin or alcohol, 

 or it may be salted. It is best to remove most of the fat and 

 all flesh from the skin. In case of moderately large fish, it may be 

 well to cut away the flesh so as to leave the vertebral column 

 intact. 



ACORN WORMS (BALANOGLOSSIDS) 



The acorn worms or balanoglossids (fig. 37) are unfamiliar even 

 to most experienced collectors, but their importance as the 

 lowest forms definitely related to the vertebrates makes them 

 valuable finds. They are soft, slimy, wormlike burrowers, from 

 1 to 20 mm. in diameter, and from 2 to 100 cm. in length. The 

 distinctive feature is the collar with projecting proboscis and 

 elongate trunk. The proboscis may be 3 to 10 times longer than 

 the collar, or there may be a single great fold on each side of 

 the trunk; otherwise all species look much like figure 37. 



Acorn worms are sluggish creatures that live in sand or mud, 

 occasionally under rocks or among seaweed roots. Black mud, 

 if the sea water is not too brackish or stagnant, and clean coral 

 sand are equally likely habitats, but wave-washed beaches are not. 

 Sand flats exposed at low tide and coral-sand tide pools are 

 typical situations. They are found in all latitudes. 



