¹ If, by longevity of forms, is understood, not the life of the individual, but the lifetime of the race, it seems hardly possible in some instances to comprehend the vast periods of time which a marine species may have existed, especially among the Mollusca. Lingulæ, differing but little from the living species, occur in the Cambrian rocks of Wales. Terebratula fimbria, of the Inferior Oolite, might (externally) pass for the living Waldheimia Australia. The King-crabs (Limuli*** of the Solenhofen stone can hardly be said to differ from those of the China seas of to-day! Prof. Owen long since pointed out that the chance of survival among land animals was in inverse proportion to their bulk; the largest being always the first to suffer by droughts and all the other causes which affect terrestrial existence, but which are unfelt by and unknown to the fauna of the sea.—Edit. Geol. Mag.