366 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Thallophyta. 

 Algae. 



(By Mrs. E. S. Gepp.) 



Flagellates and Alg/ae.* — A. Pascher gives- his views on the con- 

 nexion between Flagellates and Algae. He has studied the subject for 

 ten years, and he finds as his most important result that alga? are linked 

 on to almost all the series of coloured flagellates — or, from the point of 

 view of the phylogenetic origin of algae from flagellates, that all the 

 series of coloured flagellates (with two exceptions) lead in an absolutely 

 parallel manner to forms of cellular algae. We have thus several phylo- 

 genetically different series of brown algae and of green algae. It does 

 not, however, follow from this conclusion that all the differently 

 organized types in all these series of algae were developed simultaneously. 

 Speaking generally, the following possibilities of development in all the 

 series of coloured flagellates have been realized : 1 . The further de- 

 velopment as a flagellate. 2. The development to rhizopodial forms 

 (Rhizopod-organization). 3. The formation of principally palmelloid 

 forms (Tetrasporal organization). 4. The formation of cellular forms 

 (Protococcal organization), which in time attains the power of cell- 

 division ; and finally (a) nuclear-division goes mainly hand in hand with 

 cell-division (monergid series, Ulotrichadae-organization), or (b) nuclear- 

 division is not coupled mainly with cell-division (polyenergid, Siphonales- 

 organization). This conclusion of the author is elaborated, and ex- 

 plained by tables. 



Vegetation of the Adriatic^ — J. Schiller writes a general account 

 of the vegetation of the Adriatic, having been official botanist to the 

 Austrian-Italian Investigation. Below 200 m. there is no sessile algal 

 flora, but on surfaces above that depth vegetation fastens itself wherever 

 it is possible. The author defines three regions according to depth. 

 1. The littoral zone from high tide to the ebb line. 2. The sublittoral 

 zone from the ebb line to a depth of 40 m. 8. Deep water. Though 

 there are certain algae which last throughout the year, most species are 

 limited to a few months. Two main periods of growth occur, the larger 

 from the beginning of February to the end of May, the second from the 

 beginning of October to the middle of November. The intervals are 

 resting periods. The reasons for this are uncertain. Diatoms pre- 

 dominate down to 200 m. Pkytoplankton also reach to 200 m., but are 

 most abundant down to 75 m. — Peridinieae, Coccolithophoridae, Diatoms, 

 Flagellates, and Silicoflagellates. The growth-periods and the depressions 

 of the pelagic flora correspond with those of the stationary flora. In 

 quantity the pelagic is only about half as great as that of the Baltic near 

 Kiel. On the other hand, the quantity of organisms is very large near 

 Sebenico and in the regions influenced by the Po. 



* Ber. Deutsch. Bot. Gesell., xxxii. (1914) pp. 136-60. 

 t Urania, Wien, vi. (1913) pp. 382-6 (figs.). 



