Leeches i5 



Interstate Park in numbers insufficient to prove such a menace to 

 any child sufficiently vigorous to enter the water. Cases have been 

 reported from other localities, however, in which most serious con- 

 sequences have resulted from the attacks of leeches upon children. 

 A recent effort to secure authentic information relating to such 

 reports concerning Macrohdella decora has failed. The older 

 medical literature relating to blood-letting is filled with cases of 

 accidents to young children through the careless application of 

 leeches. 



Blood-sucking leeches may be instrumental in the transmission of 

 disease also. This may occur in two ways. A leech that has bitten 

 and been removed may shortly after bite another individual. In this 

 way bacterial or protozoan diseases may be carried mechanically. 

 This sometimes happened in the practice of leeching when the same 

 leech w'as used successively upon two patients vdthout due precau- 

 tions being taken. The danger is increased because of the habit of 

 leeches of attaching to open sores, ulcers or boils. They will also 

 attach to dead and decaying animals and thus may carry septic 

 bacteria. The second possibility is that blood-sucking leeches may be 

 the intermediate hosts of human parasitic diseases. No such cases 

 are known at present but it is known that they bear this relation to 

 certain parasites of the lower animals. 



THE SPECIES OF LEECHES IN CARR POND 



In all only nine species of leeches were found in Carr Pond and 

 several additional ones in other waters of Palisades Interstate Park. 

 Of these Helohdella stagnalis and Glossiphoma picta, the snail leeches, 

 together with Placohdella phalera, P. riigosa and P. parasitica, the 

 turtle leeches, belong to the family Glossiphonidae ; Erpohdella 

 punctata, the worm leech, to the Erpobdellidse ; and Hcemopis 

 grandis, H. marmoratis and Macrohdella decora, the jawed leeches, 

 to the Hirudinidae. 



It will be noted that there are three species of large, jawed leeches. 

 These are not discriminated by the campers, all being held equally 

 guilty of blood-sucking:. INIuch the largest of the three is HcBinopis 

 grandis (Verrill). When extended in swimming this species 

 ordinarily has a length of nine or ten inches and may be much larger, 

 but it is seldom seen abroad during the day. It is possible that upon 

 occasion it may attach itself to a bleeding wound but I have never 

 known it to do so, and, as its jaws are entirely toothless, it cannot cut 

 the skin as do the true blood-sucking leeches. Normally it burrows 

 in the wet soil at the water's edge and feeds upon earthworms, smaller 

 leeches and insect larvae. It will eat the young of the true blood- 

 sucker and probably is a factor of some importance in checking that 

 species. In Carr Pond it is very plentiful on the shores of shallows, 

 especially at one ooen area alofig the southwestern shore where there 

 is good garden soil. 



Hcemopis marmoratis is a related species but is much smaller 

 and darker colored. It seldom exceeds four or five inches in length 



