. Synopsis of the fishes of North America [microform]. Fishes; Poissons. CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGYâIV. Subclass OHONDROSTEI. i*,* â .1-J' .V- {The Sturgeons.) ' , > , . -as-' Skeleton partly cartilaginous. Ventral fin abdominal, with an entire series of basilar segments. No suboperculnm or preopercnlum. Branclii. ostegals (single or) wanting; a pnecoracoid arch ; no syinplectic bone. Mesopterygium distinct j interclavicles present.* Arterial bulb with several pjvirs of valves. Optic nerves forming a chiasma. Intestine with a si>iral valve. Air-bladder connected by a duc
. Synopsis of the fishes of North America [microform]. Fishes; Poissons. CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGYâIV. Subclass OHONDROSTEI. i*,* â .1-J' .V- {The Sturgeons.) ' , > , . -as-' Skeleton partly cartilaginous. Ventral fin abdominal, with an entire series of basilar segments. No suboperculnm or preopercnlum. Branclii. ostegals (single or) wanting; a pnecoracoid arch ; no syinplectic bone. Mesopterygium distinct j interclavicles present.* Arterial bulb with several pjvirs of valves. Optic nerves forming a chiasma. Intestine with a si>iral valve. Air-bladder connected by a duct with the oesopha- gus. Tail heterocercal, its fin with fnlcra. Skin naked or armed with bony i)lates. This group comprises two orders. (Order Chondrostd Giintber, viii, 332-347. ;j;5yfSpof, cartilage ; uariov, bono.) ANALYSIS OF ORDERS OF CH0NDR08TEI Maxillary and iutcroporcio obsoloto; skin naked; brancbiliyals cartilaginous; air- bladder cellular Sklaciiostomi, G, Maxillary and interoi)orclo present; skin witli bony shields; brancbiliyals osseous; air-bladder simple Glaniostomi, II, Okder {The raddle-fishes.) A praicoracoid arch; no sympiectic bono; premaxillary forming mouth border; no suboperculnm, preoperculnm, nor interoperculnm ; mesop- terygium distinct; basihyals aud superiorceratohyai not ossified; inter- clavicles i)re8ent; maxillaries obsolete; brancbiliyals cartilaginous. This order contains but one family, Polyodontidw. {a^Myr^, shark; (rtfJ/ju, mouth.) J Family XXV.âFOLYODONTIDiE. â {The Paddle-fishes.) ' Body fusiform, little compressed, covered with mostly smooth skin. Snout prolonged, expanded into a thin, flat blade, the inner portion formed by the produced nasal bones, the outer portion with a reticulate bony framework, the whole somewhat flexible. Mouth broad, termi- nal, but overhung by the spatulate snout, its border fornu'd by the i)ro- maxillaries, the maxillaries being obsolete. Jaws v/ith nmny fine deiid- Tlie ONte<dogical c
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectfishes, bookyear1882
