F. GEOGKAPHY. 215 



belong, for the most part, to the Rhizophorese, more par- 

 ticularly the genera Rhizophora, Kanclelia, Brugniera, and 

 Ceriops, so remarkable for their form and mode of growth. 

 Their favorite habitat is a marshy shore, free from surf, and 

 not flooded at high tide. They are shrubs rather than trees, 

 from five to twenty-five feet high. The seed germinates wdiile 

 attached to the branch, and only separates when the rootlets 

 have penetrated the slimy soil, and the young plant has 

 strenQ-th enousrh to withstand the action of the sea. The 

 stock does not enter the earth, but rather rests upon a mass 

 of roots, spreading out as they approach the ground, and 

 with their ends fixed in it. During flood tide the tips of the 

 plants only may be visible, but the retiring tide displays the 

 stems and interlacing roots, tlie latter crowded with mollusks, 

 crustaceans, and fish, left in the slime upon them. This ac- 

 cumulation becomes higher and firmer, and finally, as coast- 

 lancl, is better adapted to resist the action of the sea than if 

 the plants had rooted in the soil. With the Rhizophorece are 

 found species of similar families; for example: of -^gicerus, 

 Climatandra, and Avicennia. As the sea recedes, and these 

 plants are no longer moistened, even at high tide, they die 

 out, and are succeeded by others of diflerent mode of growth. 

 .3 C, December 23, 1872, 1246. 



EXPLOKATIONS IN THE ADEIATIC IX 1870. 



Oscar Schmidt, the w^ell-known wu'iter upon the sponges, 

 gives an interesting account of an exploration made by him 

 in 1870 for the purpose of determining the natural history 

 and physics of the Adriatic. His researches were prosecuted 

 on board the Trieste, a war vessel belonojiniij to the Austrian 

 navy ; and the results were of much interest and scientific 

 value. Dr. Schmidt used two forms of dredsres one of the 

 ordinary rectangular pattern, and the other with triangular 

 frames. The triangular dredges had three instead of two 

 bows for the ring to the rope, two of them being fastened 

 together, while the other was joined to them by a somewhat 

 thinner piece of rope, so that, in case of being hung, the fas- 

 tening would give Avayand allow the dredge to be hauled up 

 by one side. This form of dredge w'as found perfectly avail- 

 able down to a depth of 630 fathoms, especially w^hen 

 leaden Aveights of eighty pounds Avere attached in the angles. 



