22 PROCEEDINGS OF THE NATIONAL MUSEUM vol.99 



right side than on the left. I record my counts below, first for the left 

 side then for the right, respectively : 



For microdon, from the Rio Tuyra, Panama: 20-21; 21-22; 19-19; 

 18-19; 21-23; 19-20; 20-20; 19-19; 17-18; 18-18; 19-20. Also from 

 Lake Nicaragua: 18-18 and 15-15. 



For pectinatus, from the Gulf of Venezuela: 28-29; from Lake 

 Nicaragua 26-26; from Florida 25-25. 



Family DASYATIDAE: Stingrays; Rayas 



This family may be recognized by the presence of a "sting" or sharp 

 serrated spine, sometimes two of them, on the dorsal surface of the tail. 

 The pectoral fins are continuous with the snout in this family, the snout 

 scarcely projecting or not projecting in front of the general outline 

 of the disk-shaped body. 



Many persons and some uninformed naturalists have the opinion 

 that stingarees, as they are commonly called, do not have a poisonous 

 sting. Those who have studied these fishes and have had personal 

 experience with them are certain that the "sting" is highly venomous. 

 Before I cite cases of persons who have been jabbed by the spine of a 

 stingray, I shall acquaint the reader with these fishes and the nature 

 of their sting or spines. 



The stingaree is one of the rays, fishes related to the sharks and 

 greatly resembling them in structure. In shape, however, they are 

 flattened and disk-shaped and have a long tail. The rays, which bear 

 a long sharp spine, usually in the middle upper part of the tail, are 

 known as stingrays, a word corrupted to stingaree. 



Several dozen species of stingrays are known to science. These 

 creatures occur in all warm seas, as well as in many of the tropical rivers, 

 some fresh-water stingrays in South America occurring even more than 

 a thousand miles above the river mouth. Wherever stingrays occur — 

 in the seas, bays, or in rivers — they are to be found hiding on the 

 bottom in mud or sand. If disturbed, they swim with an undulating 

 motion, usually close to the bottom, and stir up a cloud of mud, then 

 come to rest on the bottom, the muddy cloud gradually settling 

 around the ray. This "mud cloud" and the camouflaged coloration 

 of the fish itself serve a definite purpose in concealing it. While thus 

 partly buried in the sand or mud bottom the stingray is in perfect 

 readiness to drive its sting into any unsuspecting victim that may 

 step on it. The weight of a person stepping on the disk-shaped part 

 of the body anchors the stingray, giving it the needed leverage to 

 whip its tail upward with uncanny precision and drive the already 

 erected spine or sting into its target. The sting on the powerful tail 

 of even a small ray only a foot across in size can pass through a 

 person's foot or into a leg bone. 



