336 ANNUAL REPORT SMITHSONIAN INSTITUTION, 194 7 



hosts is given herewith. Only the more important diseases are listed 

 and for each of them only the most important snail carriers. Insig- 

 nificant trematodes of man, such as Eeterophyes heteroyhyes^ Hap- 

 lorchis pumilio, and EchinochasmiLS perfoliatus^ have been excluded. 

 Doubtfully or accidentally implicated moUusks such as Syncera lutas^ 

 Thiara (Melanoides) tuberculata, and others have also been left from 

 the list. The trematode, Paragonimus kelUcotti^ at the bottom of the 

 table is not a human-infecting species, but its intermediate snail host, 

 Pamatiopsis lapidaria, is considered a potential host of Oriental 

 schistosomiasis. 



THE VENOMOUS CONE SHELL 



Seashell collecting and the handicraft of shell jewelry became pop- 

 ular hobbies among many of our troops stationed on remote Pacific 

 islands. The coral reefs of the South Seas and the East Indies under- 

 went the most intensive scouring for rare and beautiful specimens since 

 the days of early natural history exploration. Yet despite the many 

 hazards of reef collecting, relatively few accidents and no cases of 

 fatal bites and stings were recorded. This may be accounted for, in 

 part at least, by the wide circulation of information on poisonous 

 foods and animals given in survival handbooks by the Army and 

 Navy. 



Among the most dangerous inhabitants of the coral reefs are the 

 cone shells whose sting is equally as powerful as the bite of a rattle- 

 snake. Although the beautiful cone shells are one of the commonest 

 of Indo-Pacific mollusks, the total list of authentic cases of death by 

 their sting is not at all impressive. Of the many dozen species found 

 in this region, only five have been known to produce a venomous 

 sting. The number of cone-shell stings is few because of the shy 

 nature of the animal. Invariably a snail will withdraw into its 

 shell when disturbed, and unless the cone shell is held quietly in the 

 palm of the hand for some minutes, there is little likelihood of the 

 collector being stung. 



The apparatus for the injection of venom into the skin of the 

 victim is contained in the head of the animal. Bite, rather than sting, 

 is perhaps more descriptive of the operation. The long, fleshy pro- 

 boscis or snout is extended from the head and jabbed against the skin. 

 Within this tube are a number of hard, hollow stingers, slender and 

 long as needles. These are actually modified teeth or radulae, com- 

 monly used in other snails to rasp at their food. Under a high- 

 powered lens the teeth of the cone shell resemble miniature harpoons. 

 As the teeth are thrust into the skin, a highly toxic venom flows from 

 a large poison gland located farther back in the head, out through the 

 mouth, and into the wound through the hollow tube of the tooth. 



There have been a number of graphic accounts of the symptoms 



