PARASITES OF ANIMALS. 323 
The Broad Tape-worm of Man, (Bothriocephalus 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. Balbiani,* 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 larve of the 
cockchafer beetle, (Melolontha vulgaris, allied to our “ May- 
bugs,”) in which they develop. The ova burst in the 
* Comptes-rendus, Vol. lxix, p. 1091, 1869. 
t Sitzungsbericht der Oberhessischen Gesellschaft fiir Natur- und Heilkunde, 
March, 1871. Also, translated in the Annals and Magazine of Natural History, 
Vol. 7, p. 441. 1871. 
