AMIID^. — XXIII. 37 



33. AMIA Linnajus. {Amiatus Rafinesque.) (d/xia, ancient 

 name of some fish.) 



47. A. calva L. Bow-fin. Mud-fish. Dog-fish. "John 

 A. Grindle." Blackish olive, sides witli greenish reticulations, 

 lower side of head with dark spots ; ^ with a black ocellus edged 

 with orange at base of C. above. Head iJf ; depth 4. D. 48. 

 A. 11. Lat. 1. G7. (^18 inches; 9 24. Swamps and lakes, Vt. 

 to Dakota, Fla., and Texas ; abundant in lowlands. A fish of 

 great interest to zoologists, from its relation to earlier types. 

 (Lat., bald.) 



Series TELEOSTEI. 



We now take up the series of Teleostel proper, or true Bony- 

 fishes, a group comprising the great majority of existing fishes. 

 It is apparently descended from the Ganoid type, the Nemato- 

 gnathi being apparently allies or descendants of the Glaniostomi, 

 and the Isot>pondijli of the Ilalecomorpld. As a whole, the Tele- 

 ostel differ from the Ganoids in the more perfectly ossified skeleton, 

 the less heterocercal tail, the degradation of the air-bladder and 

 the arterial bulb, and in the simplicity of the optic chiasma. 



The Teleostei are divisible into two great groups, with rather 

 ill-defined boundaries, — the Pkysostomi, or soft-rayed fishes, and 

 the Physoclysti, or spiny-rayed. The members of the former 

 group have throughout life a slender duct, by which the air-bladder 

 is joined to the alimentary canal. In most cases the fin-rays are 

 soft, the ventrals abdominal, the pectorals placed low, and the 

 scales cycloid. Although the typical Pkysostomi differ in many 

 ways from the more specialized Physoclysti, yet as we approach 

 the junction of the two groups the subordinate differences disap- 

 pear, leaving finally the presence of the air-duct in Physosiomi as 

 the only differential character. In view of this close relation of 

 the two groups, several writers, following Professor Gill, have re- 

 moved as separate orders various aberrant forms, leaving the bulk 

 of both groups in one large order, Teleocephali, with numerous 

 suborders. We prefer to regard most of these suborders as dis- 

 tinct orders rather than to treat the heterogeneous group of 

 Teleocephali as an " order." (rtXeos, perfect ; ocrreov, bone.) 



Order XI. NEMATOGNATHI. 



This order contains several families, which agree in having the 

 subopercle wanting, the anterior vertebrie coalesced, and the max- 

 illary reduced to the bony core of a long barbel. None of the 

 order have scales, (vrjfm, thread; yvddos, jaw.) 



