126 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



EXPLANATION OF PLATES. 



Plate 1, two-third* natural size: 



Pig. 1 — Outline of adult menhaden as feeding. 1—5, gill-arches of right-hand side in natural 



position. 

 Fig. 2 — Gill-arches with branchia? and gill-rakers attached, removed from fish and arranged in order; 



1-5, bony arches ; a. b, c, x, d, y, and e are gill-rakers ; in, n, o, p, branchiae. 



Plate 2: 



Fig. 3 — Six of a series of gill-rakers attached to the gill-arch, showing the projecting rows of 

 hooks, enlarged 50 times. 



Fig. 4 — Six of the hooks attached to the gill-raker, enlarged 178 times. 



Fig. 5 — Diagram of gill-rakers in cross-section, showing angle at which hooks project from 

 their point of attachment in toward the throat cavity, and the current of water passing out 

 from it. 



Fig. 6 — Organisms from stomach of young menhaden taken from a pond closed oft' from lagoon at 

 Marthas Vineyard: p, Peridinium; d, Diatoms; t, Tintinnodea; lower half of field drawn with 

 camera from single field of the slide, magnified 178 times. 

 Plate 3: 



Fig. 7 — Organisms filtered from surface waters of the Acushnet river, showing at p the Gleno- 

 dinium which is so abundant at this locality; s, very small bean-shaped flagellates ; vegetal 

 cells are also scattered over the field. 



Fig. 8 — Organisms from the stomach of a menhaden in these same waters, showing the predomi- 

 nance of the same Glenodinium; h, Dinophysis; drawn from a single field of the microscope, 

 enlarged 178 times. 



Plate 4 . 



Fig. 9 — Organisms from stomach of fish taken in Quisset Harbor, southeastern portion of Buzzards 



Bay; p, Peridinium, the lower two large, smooth, pink-colored individuals, having the form 



of the species divergens; d, e, diatoms ; /, Tintinnodea of the genus Codonella; r, Ceratium fusus. 



Enlarged 178 diameters. 

 Fig. 10 — Organisms from fish's stomach taken at Woods Holl, in the mouth of Buzzards Bay; d, 



diatoms; p, a large Peridinium; h, Dinophysis; m, an infusorian unknown to me; t, Codonella. 



Enlarged 178 diameters. 



Plate 5: 



Fig. 11 — Organisms from food in fish's stomach taken oft'Naushou Island, mouth of Buzzards Bay, 



at the Weepecket Islands (drawn with camera from single field of microscope); /, Codonella; 



d, diatoms; r, Ceratium fusus; tn, infusorian( ?). Enlarged 178 diameters. 

 Fig. 12 — Organisms filtered from the surface waters of Buzzards Bay, in these same localities; 



p. Peridinium divergens; /and v, Codonella; d, diatoms, of which there is a representative of 



the genus Cha-toceros, with its long protoplasmic processes; e, also diatoms; h, Dinophysis. 



Enlarged 178 diameters. 



Plate 6: 



Fig. 13 — Organisms filtered from the surface of Lagoon Pond, Marthas Vineyard; d, g, and/ (/ is 



Lauderia), diatoms in chains ; p, Peridinium divergens; r, Glenodinium; c, Codonella; w, Tintinnus ; 



t, allied to Codonella; v, one of the Tintinnodea unknown to me; a, very small vegetal cells. 



Enlarged 178 diameters. 

 Fig. 14 — Organisms from the stomach of a young fish of the same locality (fish 60 mm. in length). 



2), Peridinium divergens; d, diatoms; /, Lauderia; h, Dinophysis; m, infusorian unknown to me. 



Enlarged 178 diameters. 

 Plate 7: 



Fig. 15 — Organisms filtered from surface waters of Vineyard Sound upon a bright clear morning, 



August 15; (1, large diatoms, which were A^ery abundant in the sample of water; g, Chatoceros; 



n, lllothrix zonata (?); h, Dinophysis; c, Cera Hum tripos. Enlarged 178 diameters. 

 Fig. 16 — Some of the organisms found in the stomachs of menhaden in the Acushnet River, in the 



same material figured in plate 3. g and y, alga threads ; diatoms, a, Triceratinm; b, Bildul- 



phiu; c, Stephanodi8CU8 (?); e, Navioula; j, k, Pinnularia; i, unknown diatoms; /, Merismopedia 



(alga) ; x, Discorbina. Enlarged 178 diameters. 



Plate 8: 



Fig. 17 — Outline of an adult menhaden living in Buzzards Bay, taken .Inly 20. One-half natural 



size. 

 Fig. 18 — Outline of an adult menhaden living in the extreme upper part of Waquoit Bay, taken 



August 25. One-half natural size. This region was very rich in Protophyta, especially Cya- 



nophycew, also Copepoda, 



