THE STURGEONS AND STURGEON INDUSTRIES. 
235 
small or obsolete. Stomach without blind sac. Eectum with spiral valve. Mush- 
room-shaiied pancreas, divided internally into cmcal apjiendages, the extenial inter- 
spaces between which are filled up with connective tissue, so as form an apparently 
solid organ, the cavities in which open into the upper-eiid of the duodenum through 
three passages. 
“ Large fishes of the seas and fresh waters of Northern regions. Most of the species 
are migratory, like the salmon which are found in the same waters. Genera two, 
species about twenty, although more than five times that number have been described. 
The American species especially have been unduly multiplied, particularly by Au- 
guste Dumeril, who has found upwards of forty of them in ihe museum at Paris. 
The actual number of American sturgeons does not exceed seven, and is more likely 
still less. The changes with age are considerable; the snout in particular becomes 
much shorter and less acute, and the roughness of the scales is greatly diminished. 
* * * The number of plates, although one of the best specific characters, is 
subject to considerable variations.” 
ACIPENSBR Liunieus. 
Sturgeons. 
Snout subcouical above, more or less depressed below the level of the forehead; 
more or less nearly flat below. Spiracular opening nearly twice as far behind the tip 
of the snout as the eye. Caudal peduncle of moderate length, deeper than broad, the 
lateral rows of bony scutes distinct to the base of the caudal fin. Tail not produced 
into an abortive filament or opisthure, as in SvapMrluincliops (shovel-nose sturgeons), 
but with its tip bearing caudal rays. Gill -rakers small. Pseudo branchiae or spirac- 
ular gills present. Only two sharply defined species found in the waters along the 
Atlantic coast of the United States. Possibly three other good species inhabit the 
United States; one of these is the very distinct lake or fresh- water sturgeon of the 
lake region, and two others are said to be found on the Pacific coast. 
1. A. sturio L. Common Sturgeon. 
Snout one third of the length of the head; rounded above, nearly fiat below, bluntly 
rounded in outline at tip, as seen from above, in the adult. Snout of young much 
more acute and produced than in the adult, and about half the length of the head. 
Barbels arising nearly midway between mouth and tip of snout, not reaching mouth; 
in the young longer and more slender. A median, lanceolate smooth fenestra or area 
between the parietal and frontal plates in the young, which entirely disappears with 
age. Gill-rakers small, slender, pointed, sparse, not longer than the pupil. Small 
dermal plates between dorsal and lateral rows tending to form successive oblique 
rows, in which many of these small plates tend to become lozenge-shaped. Average 
number of plates in dorsal row, 11; in lateral rows, 28; in ventral rows, 10; 4 or o 
preanal scutes. Opisthocentrous in young, mesocentrous in adult. Mouth narrow. 
Dorsal, 40-44; anal, 26-30; ventral, 26; pectoral, 35; caudal, 90; lower caudal lobe 
short; peritoneum never deeply pigmented, so that the viscera when exposed are 
nearly white. Color of skin olive-greenish above. Variety oxyrliynclms is based 
partly upon the young of this species and partly upon old individuals which retained 
tbeir unusually lengthy snouts. My own opinion is that the snout of this species 
undergoes actual shortening and loss of substance during growth. The actual varia- 
bility of this species can not be appreciated unless one has had the opportunity to 
