Siphonognathus, [674]

Siphonostoma, [634];

S. typhle, protective coloration, [172]

Sirenoidei, [149]

Sisor, [588], [589]

Skates = Raia, q.v.

Skeleton, of Enteropneusta, [14];

of Amphioxus, [119];

of Fishes, [193] f.

Skin, of Cyclostomata, [182];