358 
U. S. P. R R. EXP. AND SURVEYS—ZOOLOGY—GENERAL REPORT. 
Syn.— Polyodon, Lacep. Hist. nat. Poiss. I, 1798; &, ed. 8vo. I, 1819, 309.— Rafin. Ichth. Ohiens. 1820, 82.^Ccv. Rggn. 
Anim. I T, 1817, 142; 2d ed. II, 1829; &, ed. illustr. Poiss. 152.— Storer, Synops, 1846. 249. 
Spatularia, Shaw, Gen. Zool. V, 1804, 362.— Dum. Ichthyol. analyt. 1856, 155. 
This genus appears to be very closely allied to Planirostra, which, however, we have not been able 
to compare it to, having had no specimens of the latter genus at our command. Our compara¬ 
tive studies, therefore, rest solely upon the descriptions of Lesueur and Rafinesque. Dr. Kirt- 
land’s own account of Planirostra had to be drawn up from published data, he never having 
had the opportunity of examining that fish. 
POLYODON FOLIUM, Lacep. 
Paddle-Fish. 
Spec. Char. —Body sub-cylindrical, compressed, tapering from the thorax to the tail. Head sub-conical, expanding hori¬ 
zontally into a spatuliform snout, constituting altogether more than the half of the total length, the snout itself exceeding in 
length the remainder of the head, or head, properly so-called. Eyes very small and circular, situated opposite the extremity 
of the lower jaw. The membranous expansion of the opercle or accessory gill cover extends as far as the origin of the ventral 
fins. Above, steel blue; white beneath; gill covers maculated by stellate impression. 
Svn. — Polyodon folium, Lacep. Hist. nat. Poiss. I, 1798; &, ed. 8vo. I, 1819, 309, PI. xiii, fig. 3 — Rafin. Ichth. Oniens 
1820, 83.—Cuv. Regn. Anim. II, 1817, 143 ; 2d ed. II, 1829; &, ed. illustr. Poiss. 352— Mitchill, Hil- 
ereth & Clemens, in Amer. Journ. of Sc. and Arts, XII, 1827, 201,202, and 204.— Kirtl. in Host. Journ. 
Nat. Hist. IV, 1842, 21, PI. ii, fig. 1.— Griff. Cuv. Anim. Kingd. X, 1834, 591.— Storer, Synops. 
1846, 249. 
Spatularia reticulata, Shaw, Gen. Zool. V, 1804, 362, PI. clvi. 
Paddle-fish; Spoon-billed Sturgeon, Vernacular. 
The specimens submitted to our examination are all immature, measuring from five to seven 
inches in total length. We have ascertained the presence of spiracula, one on either side, 
occupying the same positon as in the sturgeons, close to the outer edge of the tympanic bone, 
between the latter and the gill covers. Whether pseudo-branchiae exist or not we have not yet 
had the opportunity of ascertaining. 
List of specimens. 
Catal. 
No. of 
Age. 
Locality. 
When col¬ 
Whence obtained. 
Nature of 
Collected by— 
No. 
spec. 
lected. 
I 
specimen. 
937 
3 
Young. 
Fort Pierre, Nebraska_ 
1853 
| 
Gov. 1.1. Stevens_ 
Alcoholic. 
Dr. John Evans. 
