GILL] THE FAMILY OF CYPRINIDS 209 
found to be blind, a kind of film covering the eyes and even part of 
the head. After much investigation, the gentlemen named were 
convinced that the mortality was caused by a toad (Bufo calamita). 
“They examined all the carp in the pond, and found squatting on 
the head of each of those that were diseased an enormous toad, the 
fore-paws of which were placed on the two eyes of the unfortunate 
fish. Thus, this ugly batrachian, which presents so stupid an aspect, 
has yet sufficient intelligence to assume the offensive and to over- 
come a large fish. It has not agility and energy, but it has cunning 
and perseverance. It would appear to kill by exhaustion, but it 
remains to be ascertained whether the acrid secretion of the skin 
assists in the conquest.” 
Such assaults on a fish are the more remarkable on account of the 
specialized manner in which male frogs and toads connect with and 
grasp the females. The manner in which they do this is so charac- 
teristic that it has been utilized by some herpetologists for the classi- 
fication of the order to which they belong. The toads, for example, 
grasp the female around the body just behind the forelegs and the 
Bufo calamita has what is called a pectoral amplexation. 
The carp readily interbreeds with the goldfish (Carassius aura- 
tus), or rather with its very close poor relation, the karass (Caras- 
sius carassius) ; the hybrid has intermediate characters so distinct 
from each parent that it was formerly considered to be a distinct 
generic type and named Carpio kollarti. Hessel succeeded in getting 
young from (1) a female carp and male karass, as well as from (2) 
a female karass and a male carp, and all had the characteristics of 
Carpio kollaru. He also found that hybrids were fertile, for he 
obtained hybrids of the second degree from an original female 
hybrid (Carpio kollarti and a male carp; this was distinguishable 
“with difficulty ” from “the genuine carp.” On application to the 
palate, however, judgment was pronounced that the “ flesh was 
exceedingly poor and bony.’’ (It could have been bony only so 
far as leanness and deficiency of flesh to cover the bones were 
involved, for the number of bones must have been the same in the 
two fishes.) 
The latest use found for the carp is an eradicator of the trematode 
worm which is the cause of the fluke-disease so prevalent in some 
regions. Doctor Stiles, in 1902, published testimony to the effect 
that, since carp had been introduced into Oregon and Washington 
the disease (distomatosis or fascioliasis) had been very much re- 
duced and the reduction was attributed to the agency of the carp 
