120 BULLETIN OF THE UNITED STATES FlSH COMMISSION. 



the summer and like the others seemed to grow even richer as the early autumn 

 approached. 



Some of the organisms in the stomach of a young fish — 60 millimeters in length — 

 are shown in fig. 14 ; the same genera of diatoms are present, the same Peridinium 

 and infusoria, the same organism, a, as were found in the preceding instance, from the 

 water filtered artificially- In an adult fish of this locality are also found the same 

 organisms as are here portrayed in figs. 13 and 14; especially in some fish are great 

 numbers of the Tintinnus. If now reference be made to fig. (plate 2), an idea may 

 be given of some of the most important organisms found in this same lagoon at 

 Marthas Vineyard, but in a large pond shut off at its extreme upper end from the 

 main body of water except for two very narrow sluiceway connections. Fish were 

 here taken measuring 100 millimeters in length, and their food products represented 

 in part in fig. 6. The lower half of the field is an exact drawing of the number (in a 

 single field of the microscope) and position of the very abundant vegetal organism 

 heretofore mentioned; it comprised far the greatest part of the food material. In the 

 upper half of the drawing are represented some of the other organisms which were of 

 common occurrence in the same material. All of these are alike found in the surface 

 waters, and in the menhaden stomachs of this interesting locality. In these surface 

 waters were also found many threads of fungous inycelia, also oscillatoria threads in 

 considerable quantities. 



It thus appears that young menhaden, as soon as they can be secured, indeed, in 

 the earlier part of the season, consume the same kinds of food as the adult fish, and 

 this holds true of the other localities considered in this work. They consume the 

 copepods also, like their parents, in such numbers as these Crustacea appear. Indeed 

 the stomachs of the young fish show these organic food constituents in the clearest 

 manner, since there is less mucous and amorphous matter mixed up with them. The 

 young fish from the Acushnet estuary contain Glenodinium in the same abundance as 

 do the adults, while the young fish of each locality examined led to the same conclu- 

 sions; and figures drawn from the material upon the microscopic slide would not differ 

 essentially from the figures just described. 



The food of the menhaden is not confined to the brackish-water inlets, however, 

 for by filtering the clear blue surface waters in the open channel of Vineyard Sound 

 one can at this same season gather a very interesting array of the microorganisms 

 such as have been here considered. In fig. 15 are represented a few of the com- 

 mon forms there secured, which in some respects are different in their relative kind 

 and abundance from any other locality examined. The diatoms are represented by 

 the, large d; indeed, these were very abundant in the filtrate, insomuch that a brown- 

 ish yellow color was given to the whole mass by reason of them. There is also very 

 commonly the large Chcetoceros g. The infusorial) /i ( Dinophysis) is very common; the 

 infusorian m is also common. The Peridinium group is represented by the very 

 large Geratium tripos. A great deal of Ulothrix ( f) n is also common in this water. 

 The copepod Nauplius, y, is given simply to indicate its relative size to the unicellular 

 material. 



The drawings can of course give no conception of the delicate sculpturing, color- 

 ing, and beautiful contour lines of these organisms, but it is hoped that the relative 

 size may be gathered from them, as also some graphic idea of the general make-up 



