210 SMITHSONIAN MISCELLANEOUS COLLECTIONS [vor. 48 
which devour the young worms in the cystic stages as well as the 
snails (Limneeids) in which they pass part of their lives. 
OrHER NOTEWORTHY CyPRINIDS 
The GotprisH (Carassius auratus)has been still more extensively 
diffused throughout the world than the carp. It is of a genus 
(Carassius) distinguished from the carp by the absence of barbels 
and the development of only one row of pharyngeal teeth. The 
type of the genus is the karass, or crucian carp, and the generic 
name is latinized from the popular one. Closely related to the 
karass is the goldfish, which originally was of Chinese origin and 
in China (where it is widely known as the Ken-ju) for unknown 
time it has been the object of culture and innumerable varieties have 
been bred. (Savigny, in 1780, gave colored illustrations of eighty- 
nine varieties.) It is generally maintained that it was introduced 
into continental Europe about the early part of the eighteenth cen- 
tury, although it may have found its way there long before. Any- 
way, it was not until the eighteenth century that the fish became 
common and much cultivated; about 1730 it was introduced into 
England, and from England is was diffused among the continentals. 
It was early brought to the United States. In Europe and the 
United States, wherever the climate is not too rigorous, the species 
has been acclimatized and in the United States may be caught near 
almost every large city in some pond or other. Many of the varia- 
tions to which the fish has been subject are of the nature of mon- 
strosities, such as the double, triple or greatly extended caudal fin, 
the finless back, and the “ telescopic eyes.” 
The Tencu (Tinca tinca) is recognizable by its very small scales, 
deeply embedded in the smooth and slippery skin, which remind one 
of an eel’s. The fins are rounded rather than angulate as in most 
of its relatives, and the males are peculiar in the development of 
much thickened and flattened outer rays to the ventral fins, the 
females having ordinary rays. Sexual differentiation extends even 
to the pelvic bones.t1 The species sometimes attains a weight of 
three or four pounds or occasionally even more. It prefers still 
and rather warm waters with a muddy bottom and abundant vegeta- 
tion. In a natural condition it lives near the bottom and “is 
always working in the mud.” It has been much cultivated in ponds 
*The remarkable sexual differentiation manifest in the pelvic bones as well 
as ventral fins of the Tench was fully noticed and illustrated by Dr. Giinther 
in the Annals and Magazine of Natural History (att, 385-387, 1859). The 
plate is reproduced for this article. 
