118 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



as also oscillatoria threads. One large foraminifer was also found in the food, belong- 

 ing to the genus Discorbitia. 



Applying the same methods of procedure — i. e., comparing the organic matter 

 filtered from the water with that found in the alimentary tract of the fish — to other 

 localities, it will be seen that the organisms have certain local variations, with which 

 the stomach contents of the menhaden are again in close agreement. For instance, 

 the fish taken within the southeastern corner of Buzzards Bay have contained within 

 their stomachs organic food-stuffs which agree completely within themselves and 

 with the microorganisms free-living in the water wbere they were taken. It may be 

 observed that the quantity of food here present was much less than in those fish which 

 had been feeding in the brackish waters of other regions; indeed, one fish which had 

 taken its food during the night at New Bedford — which therefore included a large pro- 

 portion of the smaller Crustacea — contained four times as much food as ten fish taken 

 in the pounds in this corner of the bay. This is an extreme case, however, for a fish 

 feeding at daytime in the estuary contains less food than one feeding at night; while 

 the Buzzards Bay fish, entrapped in a pound, may have digested up a large part of 

 his stomach contents during the night before being taken for examination. But it 

 is undoubtedly true that the food supply of a fish in the open waters of the bay is 

 less than that of one feeding in the estuary before named. This is evident by com- 

 paring the organic material filtered from a given quantity of surface water from each 

 region; also from the contents of the stomach, and from the relative weight of fish of 

 the same length in the two regions — the fish from the bay weighing less for their 

 length than the fish from the Acushnet estuary or any other brackish- water locality. 

 An illustration of the extent of these differences is given in the outline drawings, 

 one-half natural size, of plate 8; fig. 17 was from a fish taken July 20, at Woods Hull, 

 Mass., in Buzzards Bay; fig. IS, from a fish taken August 25, at Waquoit Bay, a large 

 protected inlet with narrow opening to the sea, in which the microorganic life was 

 very abundant. The organisms from the water of Buzzards Bay may be judged from 

 plates 4 and 5. The stomach contains little food and a great deal of mucus, just such 

 as is secreted in the mouth of the fish, but the microorganisms are very characteristic. 

 Those of three different positions of the microscope are gathered into fig. 9, giving a 

 characteristic idea of the material in a given fish's food. There are new forms of the 

 Peridinium type, the large sculptured Peridinium sp., at the upper edge of the field p, 

 as well as the large, smooth, pinkish Peridinium sp. ntp in the left central part of the 

 held; also at r, half of the very much elongated Ceratium fusus. 



Perhaps the most characteristic element of this locality, however, is the large infu- 

 sorian t of the genus Godonella, of which several species are found. A review of the 

 structure and systematic arrangement of these important organisms may be found as 

 given by the studies of Geza Entz upon this group.* Also by the studies of Dr. Eugene 

 V. Daday. t The Godonella here found were of the species which are invested with a 

 test in which calcareous nodules are imbedded, and were exceedingly abundant in 

 the food of the menhaden taken in this region. There is also the diatom (e) with 

 the flatiron-shape, and the infusorian m, which hereafter becomes one of the most 

 constant features of the menhaden food. In the same manner fig. 10 shows other rep- 

 resentative organisms of this region, taken from fish entrapped at Woods Holl, on the 



* Mittheilungen aua <1<t Zoologischen Station Zu Neapel, Bd. 5, 1884, p. 389. Ibid. Bd. 6, p. 200. 

 t Mittheilnngon aus der Zoologischen Station Zn Neapel, Bd. 7, 1886-1887, p. 473. 



