60 ORDERS, SUB-ORDERS, AND FAMILIES* 



TORPEDINID^E. Body flat, broad, and smooth, and gradually passing into 

 tail. Dorsal rayed, sometimes absent ; pectorals not extending beyond 

 base of muzzle; caudal well developed. Tail with longitudinal fold 

 on each side An electric organ between the pectorals and the head. 

 Torpedo, 248, 249. 



TRYGONID.E. Body broad. Dorsal, caudal, and anal absent or rudi- 

 mentary ; pectorals skirting body and head and confluent at snout. 

 Tail long and slender without longitudinal fold. Vertical fins, often 

 replaced by strong serrated spine. Try-on, 252 



Chondrostei. (TELEOSTOMI.) PLATE xxvii. No. 220 



ACIPENSERID^;. Body long and sub-cylindrical, with five rows of bony 

 shields Dorsal near caudal ; anal nearer caudal than dorsal. Four 

 barbules on lower side of snout. Teeth minute or absent. Gill mem- 

 branes confluent at throat and attached to isthmus. Gills, four; two 

 acce-.sory gills. Branchiostegals absent. Acipenscr, 220. 



Holocephali. PLATE xxvii. No. 221. 



. Body stout, with filamentous tail. Dorsals, two, occupying 

 greater part of back, anterior dorsal with long, strong spine ; caudal 

 absent, but tail with fins on upper and lower edges similar to a dorsal 

 and anal ; anal very low Snout prominent and without appendage. 

 Single gill opening covered by fold of skin enclosing rudimentary 

 gill cover ; gill clefts, four, within the cavity. Chimara, 221 



Lophobranehii. (TELECSTOMI.) PLATE xv. Nos. 114 to 119. 



SVNGNATHID^. Body ridged or rounded. One dorsal, which is not 

 spinous ; anal absent or present ; caudal absent or present ; pectorals 

 absent or present ; ventrals absent. Snout prolonged. Mouth ter- 

 minal, small, and toothless. Gills not laminated, but of small rounded 

 tufts ; gill opening small, round, and at upper posterior angle of cover, 

 which is a simple plate. Hippocampus, 119; Nerophis, 116 to 118; 

 Siphonostoma, 114 ; Syngnathus, 115. 



PhysostOHli. (TELEOSTOMI.) PLATES xxii. to xxvii. Nos. 166 to 219. 



CLUPEID^S. Body slender, abdomen often compressed into a serrated 

 edge. Dorsal not long, with weak rays, few or moderate in number; 

 no adipose fin ; anal sometimes many-rayed. Lateral line present or* 

 absent. Scales on body, but not as a rule on head. No barbules. 

 Gill openings very wide. Pseudobranchiae well developed when 

 present. Clupea, 190 to 194 ; Engnndis, 189. 



