ORDER IV. 



PHYSOSTOMI, OR MALACOPTERI. 



The fishes of this Order are all so-called Malacopterians, that is to say, fishes whose fins are 

 composed of soft and articulated rays. They have but one dorsal fin, properly so called, which 

 is nome families, possesses a spine at its anterior margin. Sometimes, also, we observe a fatty 

 fold of the skin near the peduncle of the tail — the so-called adijjose fin. The ventrals, when 

 extant, are abdominal in their positions, and sometimes also provided with a spine upon their 

 external margin. The swimming or air bladder has an air duct through which it communi- 

 cates with the throat. 



Stn. — Phjsostomi, Mull, in Wiegm. Archiv fur Natiirg. I, 1845, 131. 

 Malacoptcri, Owen, Lect. Comp. Anat. Vetebr. 1846, 48. 



There are two tribes, or else sub-orders of Physostomians, representing the abdominal 

 Malacopterygians {31alacopterygii ahdominales) , and the apod Malacopterygians {Malacopterygi{ 

 apodes) of Cuvier's classification. 



SUB-ORDER I. 



APODES. 



The ventral fins are wanting. The pectoral fins themselves are not always present. The 

 body is elongated, eel-like in its general aspect. The dorsal and anal fins are oftentimes 

 continuous with the caudal. 



S-!ti.—Jl])odts, Linn. Syst. Nat. ed. XII, 1766.— Owen, LecL Comp. Anat. Vertebr. 1846, 48.— Bd. Iconogr. Encyl. II, 

 1850, 203. 

 MalacopUnjgii apodes (in part), Mull, ni Wiegm. Archiv fiir Naturg. I, 1543, 328. 

 Physoslomi apodes s. angmllares, Mill, in W^egm. Archiv fiir. Naturg. I, 1845, 131 & 136. 



We are not aware that any apod malacopterians, as understood under this heading, have so 

 far been noticed along the Pacific coast of the United States. They seem to be wanting even 

 in the fresh waters of California and Oregon. 



SUB-ORDER II. 



ABDOMINALES. 



The ventral fins are inserted under the abdomen, about midway between the base of the 

 pectorals and the origin of the anal ; sometimes anteriorly to the middle of that distance, some- 

 times posteriorly. 



S-in.—Mdominaks, Linn. Syst. Nat. ed. XII. 1766.— Owen, Lect Comp. Anat Vortcbr. 1846, 48.— Bd. Iconogr. 

 Encycl. II, )S50, 203. 

 MalacopUnjgii abdoininulcs, Mill, in fl'iegm Archiv fiir Naturg. I, 1843, 317. 

 Physoslomi abdominalcs, MOll. in Weigm. Archiv fiii- Naturg. I, 1845, 131 & 136. 



