Typographical errors corrected by the etext transcriber:
averge depth=> average depth {pg 302}
produces these montrosities=> produces these monstrosities {pg 348}
secured a specimen of two=> secured a specimen or two {pg 360}
are always strictly cleanly=> are always strictly clean {pg 368}
Préjavelsky, Russian explorer, 276=> Préjavalsky, Russian explorer, 276 {index}