766 FISHES—ACIPENSERID A. ° 
knowledge of the priority of other names, and therefore worthy of notice 
only for censure of its author. 
ORDER 3. CHONDROSTEI. THE CHONDROSTHANS. 
Body elongated, covered with aseries of bony plates; tail heterocercal; skeleton cartila- 
ginous; mouth small, inferior, without teeth ; no branchiostegal rays; ventral fin with 
an entire series of basilar segments; no subopercle or preopercle; interopercle and 
maxillary present; branchihyals osseous. This group contains but the single family, 
Sturgeons or Acipenseride. (Chondros, cartilage; osteon, bone). 
FAMILY III. ACIPENSERIDA. THE STURGEONS. 
Body elongated, subterete, protected by five rows of large bony shields, the lower row 
sometimes deciduous in old specimens; the shields are usually provided each with a 
hooked spine; between these rows are usually smaller rough plates; snout produced ; 
mouth entirely inferior, much behind the tip of the snout, protractile, toothless; four 
barbels in a transverse row in front of the mouth; vertical fins with fulcra; dorsal fin 
placed far back, nearly opposite the anal; ventral fins present, posterior; pectoral fins 
large, inserted low; air bladder large, not cellular; stomach not cecal, with pyloric 
appendages; intestine with a spiral valve. Young Sturgeons have the scales rougher 
and the snout longer and more pointed than it is in the adult. 
Large fishes, inhabiting the fresh waters of northern regions, some of them marine and . 
entering the rivers. Genera two, species twenty-five or more. Most of them are valued 
as food. 
ANALYSIS OF GENERA OF ACIPENSERIDA., 
*Rows of bony. bucklers distinct from head to tail; spiracles present; snout sub-coni- 
cal, rather narrow. 5 : : , 6 6 : ‘ ACIPENSER. 4. 
**Rows of bony bucklers all confluent on the tail; no spiracles; snout rather broad, 
triangular, depressed. : : 6 5 : 6 SCAPHIRRHYNCHOPS. 5. 
Genus 4. ACIPENSER. Linnezus. 
Acipenser, LINNEUS, Syst. Nature, 1858. 
Type, Acipenser sturio, L., the Common Sea Sturgeon. 
Etymology, Latin Acipenser, a Sturgeon, said to be from acus, sharp, and pinna fin. 
Sturgeons with the tail subterete, the rows of bony bucklers not being confluent on 
it; spiracles present ; snout sub-conic, narrowed ; tail not ending in a filament. This 
genus as here understood comprehends all but one of the known species of Sturgeons. 
Some of them are marine; others are confined to the fresh water lakes and rivers. 
4, ACIPENSER RUBICUNDUS LeSueur. 
Lake Sturgeon; Beck Sturgeon. 
Acipenser rubicundus, LESUEUR (1818), Trans. Am. Philos. Soc., i, 388.—GUNTHER, Cat. 
Fishes, Brit. Mus., vii, 338.—KIRTLAND, Bost. Journ. Nat. Hist., iv, 303.—MILNER, 
Rept. Comm. Fisheries, 1872-73, 67, and of authors generally. 
