84: TKAWLS, DKEDGES, AND TOWING-NETS. 



which materials for investigation are gathered. Two methods are prac- 

 tised, according to the sort of animals desired or hoped for. If mollusks,; 

 sea-urchins, star-fishes, annelids, or mature non-swimming animals gener- 

 ally, or some kinds of bottom-feeding fishes are wanted, then the launch 

 is sent out to trawl. 



The trawl used by Mr. Agassiz. is a miniature of the improved appa- 

 ratus designed by him and employed in his deep-sea dredging in the West 

 .Indies on board the Coast Survey steamer Blake. It consists of a pair of 

 IPs set on edge and fastened in that position by horizontal connecting 

 bars of iron. Behind this frame so constructed is fastened a sack of chain- 

 netting or canvas, or both, and in front a sort of bail-handle to which the 

 drag-rope is attached. It is of no consequence upon which side the trawl 

 falls when thrown overboard, since the round ends of the IPs give equal 

 runners on both sides ; and, as it is pulled along, the weight, position, and 

 blade-like form of the lower bar cause the machine to hold to the bottom, 

 and scrape every easily movable thing into the strong bag which trails, 

 open-mouthed, behind. The " feel " of the rope tells the dredger when it 

 is full; it is then hauled up hand over hand or by means of a windlass, 

 and its contents are emptied out and sorted before the. next load arrives., 

 Dredging in Newport harbor, or, as we used to do it back and forth 

 through Vineyard Sound (to the great perturbation of weak stomachs), is 

 a very simple matter; but when it comes to dropping the great deep-sea. 

 dredge two miles or more, and taking all day to the experiment, with the 

 help of a donkey-engine, it becomes an art. In the two cases the appa- 

 ratus differs little, except as to size and strength. 



The laboratory I am describing, however, is connected, thus far, main- 

 ly with inquiries into the embryology and youthful life of fishes, and 

 the embryology of radiates, Crustacea, and worms. Materials for this, in 

 the shape of eggs and larvae, are almost wholly to be got just under the 

 surface of the sea, where the wandering, playful children of all sorts of 

 sea life — fishes, mollusks univalve and bivalve, crabs and shrimps, jelly- 

 fishes, sea-stars, urchins, worms, etc., etc. — swarm and drift in happy aim- 

 lessness until their ranks are thinned by countless enemies, and the survi- 

 vors sink to safer depths or settle on some public and pre-empted home- 

 stead among the surf -showered rocks. When the glare of the sun has left 

 the water, and the tide stands high off the Torpedo Station, or is just 

 beginning to settle seaward at Beaver Tail, the professor and his students 

 slowly cruise in search of such tiny prey.. Behind them is towed a gauze 

 net, which skims the surface and ingulfs every unlucky midget in its path, 

 while all hands continually dip up at random gauze dipperfuls ,of water 



