Jordan and Evcrmann. — Fishes of North America. 1721 



edges, and with distinct teeth in the jaws. There is hut 1 family, the 

 Osiraciida;, a singular offshoot from the Sclerodermi. (odrpaKov, a hard 

 shell, like that of an oyster; 8i)pf.ia, skin.) 



Family CLXXI. OSTRACIIDAE. 

 (The Trunk Fishes.) 



Body short, cuboid, tri(|netron8 or pentagonal, covered by a carapace 

 formed of firmly united polygonal hony patches, the jaws, bases of the 

 fins, and caudal peduncle free and covered by smooth skin. Mouth small ; 

 each jaw with a single series of long, narrow teeth. Maxillaries and pre- 

 maxillaries firmly united. Gill opening a nearly vertical slit, below and 

 behind the eye. Dorsal fin single, short, without spine ; anal short, sim- 

 ilar to dorsal ; candal rounded ; no ventral fins ; vertebr;e 14, the anterior 

 9 elongate, the last 5 extremely short; no ribs. Genera 3; species about 

 20, all of the tropical seas, living near the bottom in shallow waters. 

 The species of this group are so singular in appearance and so easily 

 preserved that they have been common in collections ever since the col- 

 lecting of tropical curiosities began. The 4 American species were well 

 known to Artedi and Linna?us. "The locomotion of the trunk fishes is 

 very peculiar. The propelling force is exerted by the dorsal and anal 

 fins, which have a half rotary, sculling motion, resembling that of a screw 

 propeller; the candal fin acts as a rudder, save when it is needed for 

 unusually rapid swimming, when it is used as in other fishes; the chief 

 function of the broad pectorals seems to be that of forming a current of 

 water through the gills, thus aiding respiration, which would otherwise 

 be difficult on account of the narrowness and inflexildlity of the branchial 

 apertures. When taken from the water, one of these fishes will live for 

 2 or 3 hours, all the time solemnly fanning its gills, and when restored to 

 its native element seems none the worse for its experience, except that, on 

 account of the air absorbed, it can not at once sink to the bottom " (Goode. ) 

 {Schrodermi, group Ostraciontina, Giiuther, Cat., ^'iii, 255-268, 1870.) 



a. Carapace forming a contijiuoiis bridge behind the anal fin ; ventral surface not cari- 

 nate ; caudal rays 10. 

 b. Carapace triquetrous, or 3-angled, a median dorsal ridge pud a ridge on each 

 side of belly prominent ; ridge on each side of back obsolete or -wanting. 



Lactopheys, 676. 



676. LACTOPHRYS, Swainson. 

 (Three-angled Truxk-fishes.) 



Ostracion, part, Linnaeus, Syst. Xat., Ed. x, 330, 1758 (many species; first restricted by 



Swainson to 4-angIed forms, cubicus taken as type). 

 Lactophrys, Swainson. Nat. Hist. Class'n Fishes, n, 194, 324, 1839 (trigonus, etc. ; restricted 



to species trigonal, -with spines). 

 Rhinesomus, Swainson, Xat. Hist. Class'n Fishes, 11, 194, 324, 1839 {triqrieter). 

 Ostracion, Kaup, Archiv Naturg. 1855, 214 (triqueter; restricted to trigonal forms, the 



4angled forms being named Oibolion). 

 Acatithostracion, Bleekek, Atlas Ichthyol., V, 27, 1862 (quadricomis). 

 Lcetophrys, Bleeker, Atlas Ichthyol., v, 27, 1862; corrected spelling. 

 Chapimts, Jordan & Evebmann, CheckList Fishes N. and M. A., 424, 1896 (bicaudalis). 

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