8 Algae. 



agents dans la nature. Ce n'est qu'ä des temperatures tres basses ou 

 tres eleves que la Physiologie de la zoospore commence ä etre 

 affectee. P. Hariot. 



Gain, L. et R. Mirande. Note sur les Algues recueillies par 

 Mr. L. Garreta aux iles Salvages et Canaries. (Bull. Mus. 

 nat. Hist. nat. 7. p. 479—481. 1912.) 



Les auteurs de cette note donnent la liste des Algues recueillies 

 en juin 1911 par Garreta ä bord du Yacht de E. Bretel. II existe 

 une grande analogie entre la flore marine des Salvages et celle 

 des Canaries. La liste comprend 30 especes: 2 Phycochromacees, 

 6 Chlorophycees, ö Pheophycees et 16 Floridees. A signaler: Cys- 

 toseira canariensis Sauv., Callithaninion elegans DucL, Chondria te- 

 nuissima (G. et W.) Ag., Polysiphonia Brodiaei Dillw., non signales 

 aux Canaries, Ricardia Montagnei D. et S. qui parait abondant 

 sur Lanrencia obtiisa. La presence du Ricardia dans l'Atlantique 

 est interessante; c'est une espece ä rechercher, etant donnee la fre- 

 quence de son hote. P. Hariot. 



Gran, H. H., Preservation of Samples and Quantitative 

 Determination of the Plankton. (Cons. perm. int. pour 

 l'Explor. de la Mer, Public, de Circonst. N'J. 62. 15 pp. Copenhague, 

 Avril 1912.) 



The methods hitherto used for quantitative investigation of the 

 microplankton (f. i. that of Lohmann) require examination of the 

 material in the living condition immediately after the capture; thus 

 it was impossible to collect a large material for working up later in 

 the laboratory. After various experiments the author has succeeded 

 in finding a method which makes it possible to preserve water- 

 samples containing microplankton from the coastal waters, where 

 the calcareous organisms {Coccolithophoridae) are as rule of subordi- 

 nate importance; on the other band for samples from the open 

 ocean containing many calcareous organisms no preserving method 

 has yet been found. 



The method used by Gran is the following: The water-samples 

 are taken directly from the water-bottle into bottles with ground 

 Stoppers. The bottles must first have been well cleaned with con- 

 centrated sulphuric acid and completely freed from dust. In general, 

 bottles of 250 cc. capacity are sufificiently large. To the sample is 

 added immediately 10 cc. of Fleming's strong Solution (15 vols. 

 \^% chromic acid, 4 vols. 2*^/o osmic acid, 1 vol. glacial acetic acid). 

 Samples preserved in this way may be kept for months without 

 the plankton organisms changing. The investigation of the preser- 

 ved material is carried out preciseiy in accordance with Lohmann^s 

 centrifuge-method. The drop on the bottom of the centrifugal tube, 

 which contains the plankton, is draw up in a pipette and examined 

 on an object-glass marked with lines at a mutual distance of 0.4 mm. 

 The pipette is washed in the centrifugal tube with distilled water 

 which is centrifuged and afterwards examined in the same manner. 



After the description of the method the author publishes the 

 results of some series of investigation in the Skager Rak. From 

 these it is evident that an exact quantitative investigation of the 

 plankton at dififerent depths is able to give interesting information, 

 not only regarding the biological conditions of the species, but also 

 regarding their dependence on the currents. "Such an investigation, 



