FISHES OF PENNSYLVANIA. 5 

ORDER GLANIOSTOMI (THE STURGEONS), 
* 
Famity ACIPENSERIDA. 
Genus SCAPHIRHYNCHUS Hecke. 
The genus Scaphirhynchus is distinguished from the genus of the 
common sturgeons, Acipenser, by the absence of spiracles and by the 
complete armature of the tail with bony plates. Tail much depressed, 
wider than deep. Snout depressed, acutely triangular in shape and in 
the form of a spade. In the young the tail ends in a long filament. Gill 
rakers fan-shaped. Pseudobranchiz not developed. 
Body elongate with tapering snout and tail. It has rows of bony 
plates along the top of the back, the median line and near the abdomi- 
nal outline. Under the dorsal these shields are confluent and are con- 
tinued over the top of the tail, forming a complete bony covering. 
5. Scaphirhynchus platyrhynchus Rarrinesqve. 
The Shovel-nosed Sturgeon. 
The body of the shovel-nosed sturgeon is elongate. the tail slender and depressed, 
the head broad, snout long and flat or shovel-shaped. The tail ends in a filament, 
which in the young is rather long, often wanting in the adult. The head is con- 
tained about three and one-half times in the length to the end of the vertebra. 
There is a small spine in front of the eye, another at the posterior edge of the shovel, 
and in the young there are several spines on the snout. A pair of barbels on the under 
surface of the snout, situated nearer the eyes than the tip of the snout, their distance 
from the eye being two-ninths length of the head, while their distance from the snout 
is more than one-third of the same length. The barbels have rather numerous 
minute filaments along their edges. The length of the barbels is rather more than 
one-fourth thatof thehead. The eyeis very small, less than one-seventh the posterior 
portion of head. The posterior nostril is slightly obliquein position, longer than the 
eye; anterior nostril about as long as the eye. The height of the body is contained 
seven and one-half times in the total without caudal, and is nearly half length of head. 
The length of the snout is contained six and one-half times in total without caudal. 
The postorbital part of the head is about two-fifths length of head. The pectoral has 
a very broad base, and its length equals height of body. The distance from the pec- 
toral origin to the ventral origin about equals length of head. The ventral isa little 
more than one-half as long as the snout. The dorsal and anal fins are small and 
not so far back as in the lake sturgeon. The dorsal origin is over the twenty-sixth 
scute of the median series. The length of its base is half length of snout, about 
equal to its longest ray, which is more than twice the length of its last ray. The 
anal is under the posterior part of the dorsal ; its longest ray nearly one-third length 
of head, and twice the length of anal base. The least height of caudal peduncle is 
scarcely more than one-seventh the greatest height of body. The lower lobe of the 
caudal fin is less than one-third as long as the upper, which is longer than the head. 
The gill rakers end in several points. Dorsal shields from fifteen to eighteen ; me- 
dian shields, forty-one to forty-six, and ventral shields from eleven te thirteen. The 
rays of all the fins are slender and numerous. Color very pale yellowish, some- 
times whitish. 
