LIST OF ILLUSTRATIONS. 



DREDGING APPAEATUS. 



Page. 



Platb 1. — Unitert States Fish Commission steamer Fish Hawk 50 



II. — Port side of main deck, showing portion of hatching machinery 54 



m. — Hatching cylinders. ])ort side 54 



IV. — One hatching cone, 3 hatching cylinders, 1 siphon funnel, 2 spawn pans, 1 spawn 



pail, 1 spawn dipper 54 



V. — Hoisting and reeling engine, from forward, looking aft .t4 



VI. — Hoisting and reeling engine from aft, looking forward 'A 



VII. — Safety liooks, showing spring 54 



VIII. — Accumulat T, with dredging block hooked, safety hook, brass washer 54 



IX. — The beam trawl ready for lowering rA 



X.— Dredge safety hook, water bottle, dredge- weight, and tangles, Chester rake 



dredge 54 



XI. — The table sieve and cradle sieve, hopper and tray exposed 'A 



XH. — Main deck, starboard side, table sieve, swinging table, and collecting apparatus 54 



XI 11. — Sounding machine, with Negrettiand Zambra deep-sea thermometer descending. 54 



XIV. — Sounding machine, with Negretti and Zambra deep-sea thennometer ascending. 54 



XV. — Sounding machine, with Bassnett's ]>atent atmospheric lead 54 



XVI. — The Negretti and Zambra deep-sea thermometer, with wooden frame and metal 



case 54 



XVn. — The Miller-Casella deep-sea thei'mometer in and out of case 54 



XVni. — Hilgard's ocean salinometer 54 



HATCHING APPARATl-8. 



Figure 1. — Vertical sectional view of the aerator 55 



2. — End view of the aerator 56 



3. — Nest of three hatching (rones and siphon tank 57 



MACKEREL FISHERY 



Plate I. —Diagram showing the catch of mackerel by citizens of Massachusetts between the 



years 1804 and 1881, inclusive 170 



ANNELIDA CH^TOPODA. 



Plate I. — Ilteoue ciuerea, Podarkc ca;ca, Hesione agilis 744 



II. — Syllides convolnta, Streptoayllis arenae 744 



III.— Streptosyllis arenas, Sphaerosyllis brevifrons, Paedophylax hebes. Nereis tenuis .. 744 



IV. — Nereis tenuis, Staurocephalus csecus 744 



V. — Goniada gracilis, Spio Kathbuni, Streblospio Benedicti Webster 744 



VT. — Spiophitnes Verrilli, Xicolea viridis, Plata intermedia 744 



VII. — Pisla palmata {Verrill), Potamilla neglecta Malmgren, Thaumastoma singulare . - 744 



Vm. — Sphaerosyllis longicirrata, Eulalia diibia 



XI 



