2. scAPHiRnYNcnus. 345 



Acipenser rAntaceus) alcxandri, Dinn6ril, I.e. p. 183, pi. 15. fip 1 



( ) oliyopcltis, Dumcril, I. c. p. 184, pi. M tijr. o. 



Snout long, rather longer than the remaining ])art of the head • 

 barbels simjile. Osseous shields well developed, 9-11 on the back! 

 J7-2y * on the side, and 9-10 on the abdomen. Skin with nume- 

 rous stellate ossifications, unequal in size. Part of the anal fin 

 below the dorsal. D. 30-37. 

 California. 



2. SCAPHIRHYNCHUS. 



Scaphirhyuchus, Heckel, Ann. Wien. Mm. i. 1835, p. 71. 



Posterior part of the tail attenuated and depressed, so that it is 

 entirely enveloped by the osseous scutes. Spiracles none. The 

 caudal rays do not extend to the extremity of the tail, which termi- 

 nates in a filament. 



Mississippi and tributaries. 



1. Scaphirhyuchus cataphractus. 



Acipenser cataphractus, Gray, Proc. Zcml. Soc. 1834, p 122 

 Scaphirhynchus rafiuesquii, Hevhl, I. c. pi. 8; Brutzer, Be Sc. r. dis- 



qidsitiom-s a/iafovu'crf, Dissert. Borpat. 18U0. 

 Acipenser platorliyuchus, {liq/cncsque) Xirtland, JSost. Joum. Nat 



H>d. V. p. 25, pi. 8. fig. 1. 

 Scapliirhyiichus platirhvnchus, Girard, U. S. Pac. M. JR. Exo Fish 



p. 357. ^' 



Snout spatulate ; 15-16 scutes along the back, 40-46 on the side 

 and 10-13 along the abdomen. ' 



Mississippi and tributaries. 

 a-h. Stuffed, 4 and 2^ feet long. Ohio. 



c. Fine specimen. K"ew Orleans. Purchased of Mr. Cuming. 



d. Half-grown. North America. Purchased of Mr. Brandt. 



e. Half-grown : stulfed. North America. 

 /. Adult: skeleton. 



* The number 49 is a misprint in Dr. Ayres's description. 



