494 BULLETIN OF THE BUREAU (fP FISHERIES. 



4. SOME STATISTICS RELATIVE TO THE DISTRIBUTION OF ALGyE IN BUZZARDS BAY AND 



VINEYARD SOUND. 



It is a very difficult matter to make in detail a satisfactory comparison of the algal 

 flora of Woods Hole and its vicinity with those of other coasts, chiefly for the reason 

 that the life conditions are so diverse in different sections of the region and at different 

 seasons that there are in reality several floras to be considered. These have been 

 described in the account of the principal formations which may be distinguished (section 

 II, chapter iii, pages 468-475), but far more nuist be known of their composition and 

 habits at other seasons of the year than the summer before their limits can be defined 

 with exactness. The general characteristics of the summer flora of the wanner waters 

 of the region, which is a part of the flora of Long Island Sound, are outlined in the 

 introduction to section 11, chapter i, pages 443 and 444. 



Comparative studies of algal floras are also rendered very difficult because the floras 

 have generally been described more with regard to the variety and number of species 

 than with respect to the quantities of the dominant forms. A comparison of two lists 

 of species may show that a very large proportion, perhaps a majority of the fonns, are 

 not the same, and yet when judged quantitatively, i. e., by the total mass of vegetation 

 composed of species common to both, the two floras might be considered as essentially 

 similar. We have examined lists of species published by surs'cys or from stations on the 

 Scandana\'ian coast, the Faroes, Denmark. Clyde Sea area, Plymouth, the Irish Sea, 

 Naples, etc., and considered the possibiUty of drawing up comparative tables of floras, 

 but we must confess that to us there seemed so little promise of satisfactory results that 

 the work was not undertaken. 



In connection \\dth the zoological data presented in section i, chapter in, statistics 

 were tabulated for the distribution of the four classes of algae and of Zoslcm marina 

 as determined by the dredging operations in Buzzards Bay and Vineyard Sound. The 

 results of that tabulation are presented below. Of especial interest are the statistics 

 for the quantity of vegetation over three types of bottom: Division A, "sand," including 

 bottoms recorded as pure sand or sand and shells (excluding bottoms containing stones, 

 gravel, or mud); division B, "gravel and stones," including records which list either of 

 these ingredients singly, or in combination with one another or with sand (excluding 

 bottoms containing mud); di\-ision C, "mud," including bottoms recorded as of mud, 

 muddy sand, or sandy mud (excluding bottoms containing gravel or stones, but including 

 those in which shells are listed). Finally there is presented a table which lists those 

 species that were of such general distribution as to occur at one-fourth or more of the 

 total number of stations, at one-fourth or more of the stations dredged by the Fish 

 Hawk and Phalarope in both the Bay and Sound, and at one-fourth of the stations of the 

 three types of bottom designated as A, B, and C. These tables follow in the order 

 outlined above. 



Average Number of Genera and Species of Plants Taken per Dredge Haix for the 458 



Stations of the Regvlar Series. 



Groups. Genera. Species. 



Cyanophyctse 



Clilorophyceie 



Phaeophyceae r.i 1.3 



Rhodophyceae 4.3 4.6 



Zostera mazina 



