THE LOWER FISHES 169 



coloration of the round sting ray. This species eats invertebrates mostly and can 

 produce shocks of thirty-seven voks. It matures at 9 to 10 inches in length and 

 reaches 18 inches. Found from Florida and Texas south to Brazil. 



The True Rays: Superfamily Myliobatoidea 



The remaining rays are grouped in a single superfamily. All have the tail very 

 well marked off from the body, usually like a whip, with one or several dangerous 

 poison spines at its base (exceptions to this are found among butterfly and devil 

 rays). This tail spine can be a very dangerous defensive instrument which can 

 produce excruciating pain. Known remedies are a warm Epsom salts bath or an 

 injection of 5 per cent permanganate of potash solution (Condy's Fluid). The 

 injection of antibiotics or other antiseptics may also be of value. These are 

 principally shallow-water fishes of the tropics and subtropics. Some enter fresh 

 water. The species vary in size from under a foot to 23 feet in width. They are 

 all ovoviviparous. Several species can utter a grunting sound. 



STING RAYS: Family Dasyatidae 



The discs are usually rhomboid but may be round (in the round sting 

 rays). The tail is long and whiplike and bears no fins (except for round 

 sting rays). These rays all have a long serrate spine at the base of the tail. This 

 spine is not only poisonous, but it is large enough to cause a dangerous wound 

 by itself. The stingers may vary from an inch or so to over a foot long. If one is 

 lost or worn out another grows in its place so that two or even three may be 

 present at once. The spine appears to be used mostly in defense but may 

 rarely be used off^ensively. It was a matter of debate for many years whether 

 or not the spine actually carried a poison. It was thought that the jagged wounds, 

 and mucus and other foreign matter introduced into the wound, were enough 

 to cause the extreme pain, swelling, cramps, inflammation, gangrene, or, rarely, 

 death. (Stings are not always serious, but the fact that they may be so should 

 be warning enough.) Then it was discovered that the narrow grooves along each 

 edge of the spine contained a glandular, poison-secreting tissue. Furthermore, 

 the poison is of a virulent nature. Poison glands may also be present at the base 

 of the spine. 



Sting rays are usually not active, lying buried in sand with only the eyes and 

 spiracle showing. However, .they are not nearly as sluggish as torpedoes and 

 may frequently be seen swimming over reefs and sandy bottoms, being capable 

 of considerable speeds. They are mostly crustacean- and mollusc-eaters, but do 

 take fishes also. They commonly stir up the bottom with their pectorals in search 

 of food. At times they are extremely abundant over shallow, sandy bottoms, 

 almost seeming to pave the bottom. Large ones are powerful, but inoffensive. 

 The authors, in order to stir one very large southern sting ray for purposes of 

 photography Qfigs. 71 and 76X grasped it by the tip of the tail. It rose, circled 

 slowly, swam a short distance, and sank to the bottom, burying itself by throwing 

 sand over its back with its pectoral fins. This afforded an excellent chance to 

 observe and photograph its exceedingly graceful and beautiful "flight," not 

 forgetting, of course, that this seemingly inoff^ensive beast possessed a formidable 

 weapon. Sting rays are ovoviviparous and found in warm shallow waters the 

 world over. 



