THE fourth volume of this admirable tropical flora has lately appeared, and contains the Dicotyledons from Leguminosa to Callitrichacea (on the Englerian system). It maintains the high standard of its predecessors, and shows a great advance upon some well-known tropical floras in being illustrated by excellent text figures, and not by a series of separate plates, which are usually troublesome to consult. The index is also convenient in being only a single list of both scientific and popular names and synonyms. Turning to the contents of the book, which have been worked up with much care and after consultation of all the older authors and collections, an interesting feature that may be noticed is the extraordinary generic similarity of the flora to that of other islands, even at immense distances from Jamaica. In the Leguminosæ, for example, the first family in the volume, 118 Jamaica species, or 80 per cent., belong to genera that also occur in Ceylon, 74 per cent. to genera occurring in Formosa, and even in the case of so far distant an island as New Caledonia 63 per cent. of the Jamaica species belong to common genera. It is clear that the islands on the whole contain the older genera, which have been able to reach them. Of the Jamaica genera of Leguminosa 70 per cent. are cosmotropical, and only 14 per cent. are Confined to the New World. Again, one notices that the proportion of endemic species is small in Leguminosæ, and larger in Euphorbiacea and some of the other families, just as in other, floras. It would appear a promising piece of work to make a careful statistical study of numbers and proportions of endemics in many countries, for it evidently follows definite, if perhaps recondite, laws.