766 FISHES — ACIPENSERIDJE. 



knowledge of the priority of other names, and therefore worthy of notice 

 only for censure of its author. 



ORDER 3. CHONDROSTEI. THE CHONDROSTEANS. 



Body elongated, covered with a series of bony plates; tail heterocercal ; nkeleton oartila- 

 ginons ; mouth small, inferior, without teeth ; no hranohiostegal rays ; ventral fin with 

 an entire series of basilar segments ; no subopercle or preoperele ; interopercle aiid 

 maxilliiry pre.-eDt; brauchihyals osseous. This group contains but the single family, 

 Sturgeons or Acipensetidw. (Chondros, cartilage ; Oiieon, bone). 



FAMILY III. ACIPENSERIDiE. THE STURGEONS. 



Body elongatid, snbterete, 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 sdp tiller 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 fclcra ; dorsal fin 

 placed far back, nearly opposite the anal ; ventral fins present, posterior; pectoral fins 

 large, interted low; air' bladder large, not cellular; stomach not coical, with pyloric 

 appendages ; intestine with a spiral valve. Young Sturgeons have the scales rougher 

 and the snout lor.j^er and more pointed than it is in the adult. 



Large fibhes, inhabiting the fresh waters of noitliern regions, some of them marine and 

 entering the rivers. G„uera two, species twenty-five or more. Most of them are valued 

 as food. 



Analysis of Gknera op AciPENSEBiDis. 



*Eows of bony buckleis distinct from head to tail ; spiracles present ; snout sub-coni- 

 cal, rather narrow ... Acipbnskr, 4. _ 



**Eows of bony bucklers all confluent on the tail ; no spiracles ; snout rather broad, 

 triangular, depiesied Scaphirehynchops. 5. 



Gends 4. ACIPENSER. Linnajus. 



Aeipeiiser, LiNNiEUS, Syst. Naturae, 1858. 

 Type, Acqienaer aiurio, L., the Common Sea Sturgeon. 

 Etjmology, Latin Acipenser, a Sturgeon, said to be from amis, sharp, andjiinna fin. 



Sturgeons with the tail subterete, the rows of bony bucklers not being conflaent on 

 it; spiracles present ; snout sub-conic, narrowed; tail not ending in a filament. This 

 genus as here understoi d 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 KtTBicuNDUs LeSueur. 



Lia^kc Stni'g^eon; Rock Sturgeon. 



Acipenser mlicmidiis, LrStjeur (1818), Trace. Am. Philos. Soc, i, 388, — Gukther, Cat. 

 Fisjhes, Brit. Mus., vii, 338.— Kirtland, Bust. Journ. Nat. Hist., iv, 303. — Milnbr, 

 Eept. Comm. Fisheries, 1872-73, 67, and of authors generally. 



