PARASITES OF ANIMALS. 323 



The Broad Tape-ivorm of Man, (BothriocepTialus latus Brem- 

 ser.) Report for 1870, p. 212. 



It has been ascertained by Dr. Koch that this species lives 

 while in the young or larval state in running streams, attached 

 to stones, instead of being parasitic in some fish, as had been 

 previously supposed. Therefore we may expect that it will, 

 sooner or later, be introduced into the streams of our own 

 country, in regions settled by emigrants from those parts of 

 Europe infested by it ; for the mature worm has often been 

 found in such emigrants in various parts of the United States. 



Echinorhynchus gigas Goeze, (See Report for 1870, p. 220.) 



This common intestinal worm of the hog, has attracted much 

 attention recently, on account of its remarkable structure 

 and mode of growth. 



It has been ascertained by Mr. E. G. Balbiaui,* that 

 although the development of the eggs commences before they 

 are laid, it soon ceases and can proceed only after the eggs 

 are discharged and fall to the moist earth or water ; that 

 several months elapse in winter before the embryos hatch, 

 and the hatching may be delayed a year without destroying 

 the vitality of the embryo ; and that the eggs will not hatch 

 in the intestine of the animal in which the adult worm re- 

 sides, but pass into the body of some other animal, where the 

 embryo passes through its first stages of growth. 



Professor A. Schneiderf has traced its development and 

 history quite satisfactorily. According to his observations 

 the history is as follows : The ova of this worm are scattered 

 upon the ground by the pigs harboring the adult worms in 

 their intestines. They are then devoured by the larvae of the 

 cockchafer beetle, (^Melolontha vulgaris, allied to our " May- 

 bugs,") in which they develop. The ova burst in the 



* Comptes-rendus, Vol. Ixix, p. 1091, 1869. 



t Sitzungsbericht der Oberhessischen Gjsellschaft fur Natur- und Heilkunde, 

 March, 1871. Also, translated in the Annals and RIagazine of Natural History, 

 Vol. 7, p. 441. 1871. 



