Family 97.—POLYDONTIDÆ. (1 Genus, 2 Species.)

"Fresh-water fishes, with wide lateral mouth and naked skin."

Distribution.—The Mississippi and Yang-tse-kiang rivers.

Sub class IV.—CHONDROPTERYGII. (Sharks and Rays.)

Order I.—HOLOCEPHALA. (Chimæras.)

Family 98.—CHIMÆRIDÆ. (2 Genera, 4 Species.)

"Shark-like marine fishes, snout of the male with a prehensile organ."

Distribution.—Northern and Southern temperate seas. Chimæra is British.

Order II.—PLAGIOSTOMATA.

Sub-order.—Selachoidea. (Sharks.)