526 "AMERICAN FISHES. 
the old species is that neither extends upwards to the high latitudes or enters 
upon a pelagic life, and consequently their common ancestry must be very 
far back, and separation must have lasted a long time. 
This species, when adult, is from five to twelve feet long, but the former 
size is very much oftener approximated than the latter. It changes consider- 
ably with age, the young having a more slender and protuberant snout, and 
the sexes also differ, the male having an oblong head and a wide and blunt 
snout, as seen from above, while the female’s head is triangular, rapidly 
narrowing from the back to the snout. 
COMMON AMERICAN STURGEON: YOUNG. 
The Sturgeon has been called “a scavenger and bottom feeder.” It is a 
grubber and digger into the bottom of river or ocean. The sensitive infra- 
rostral barbels are efficient agents for the discovery and appreciation of 
food, and these are supplemented by “the soft sensitive lobes which 
surround the entrance to the mouth more or less completely, and constitute 
a system of organs of touch by the help of which the animal is made aware 
of the presence of the living food at the bottom upon which it subsists.” 
Professor Ryder found that the “ dietary is sufficiently indicative of the mode 
in which the animals take their food, and it is probable that annelids, 
nemerteans, etc., also largely enter into the dietary of these fishes.” Professor 
Ryder further met with the remains of earth-worms in the intestines of 
young Sturgeons. In adults, he frequently found “broken fragments of 
the shells of mollusks, bivalves as well as univalves,” including “ fragments 
of Mytilus (mussels) and other brackish-water forms.” Large quantities of 
mud are also to be found associated in the intestines with the remains of 
crustaceans. 
While the barbels and lips serve to feel, the snout is used to root up food. 
At Tampa Bay, in Florida, schools were “ observed near the shore digging up 
the soft bottom of shoal places with their snouts. The object of such a 
habit would seem to be the search for half-buried mollusks, annelids, 
etc.” 
