62 



DANGEROUS MARINE ANIMALS 



grooves. Thus, a perfectly clean-looking spine can still be venomous. 

 Fig. 33 illustrates the stingray sting in cross section. Fig. 34, 

 Top shows the caudal spines of various species of stingrays. 



Medical Aspects. Pain is the predominant symptom and usually 

 develops immediately or within a period of ten minutes following 

 the attack. The pain has been variously described as sharp, shoot- 



VENTRAL 



GLANDULAR GROOVE 



LAYER OF SKIN 

 OR - 

 INTEGUMENT 



VENOM GLAND 



BLOOD VESSEL 

 BONY SPINE 



RECURVED SPINES 



INTACT STING- 



DORSAL 



Fig. 33. Cross section of a stingray sting, showing both damaged and intact 



stings. Note that the bulk of the venom-producing tissue lies sheltered in the 



glandular grooves. Even damaged stings may retain sufficient glandular tissue 



in these grooves to produce intoxication. 



ing, spasmodic or throbbing in character. The freshwater stingrays 

 are reputed to cause extremely painful wounds. More generalized 

 symptoms of fall in blood pressure, vomiting, diarrhea, sweating, 

 rapid heart beat, muscular paralysis, and death have also been 

 reported. 



Stingray wounds are either of the laceration or puncture type 

 (Fig. 34, Bottom). Penetration of the skin and underlying tissue 

 is usually accomplished without serious damage to the surrounding 

 structures, but withdrawal of the sting may result in extensive 

 tissue damage due to the recurved spines. Swelling in the vicinity 

 of the wound is a constant finding. The area about the wound at 

 first has an ashy appearance, later becomes cyanotic and then red- 

 dened. Although stingray injuries occur most frequently about the 

 ankle joint and foot as a result of stepping on the ray, instances 

 have been reported in which the wounds were in the chest. 



