Collecting 9 



The clam hoe and the hooker. These instruments are used for digging 

 in shallow water or on the exposed sand or mud flats. The clam hoe 

 (Fig. 8) has four prongs about i 1 ^ inches wide and from 12 to 14 inches 

 long, and a strong wooden handle about 4 feet in length. The instru- 

 ment is suitable for digging in coarse sand or gravel. The hooker 



Fig. 8. — The clam hoe. 



Fig. 9. — The hooker. 



(Fig. 9) used in digging in the hard mud, has four thin, sharp prongs and 

 a short handle. 



The shovel. An ordinary steel shovel is a valuable tool for collecting 

 animals living in sand or mud on the beaches or in shallow water. 



The dredge. The dredge is the most efficient instrument for collecting 

 bottom dwelling forms regardless of the depth of the water. Dredging 

 at great depths is a difficult operation requiring costly equipment, but 

 dredging in shallow water not exceeding 100 feet, may be carried out 

 from a small boat and does 

 not require special machinery. 

 There are many types and sizes 

 of dredges, ranging from small 

 instruments about 1 foot wide 

 to large commercial oyster 

 dredges several feet wide and 

 having a capacity of over 25 

 bushels. The description given 

 here refers only to small in- 

 struments that may easily be used by the collector of scientific material. 



The dredge is always made of a rigid iron frame to which a bag made 

 of heavy netting or interwoven chain rings is attached. The most com- 

 monly used type is the so-called scraper or scallop dredge (Fig. 10) 

 which consists of a triangular framework with an iron blade (B), 2 inches 

 wide, set at an angle so as to dig into the bottom. On the upper side a 

 raised cross bar connects the two arms. The net with a wooden hori- 

 zontal bar at the end is fastened to the cross bar and to the top of the 

 blade. Additional weight (A) may be put on the cross bar if it is desired 

 that the instrument cut deeper into the bottom. The dredge shown in 

 figure 10 has a metal sheet (A) which serves the double purpose of pro- 



Fig. 10. — The scallop dredge. 



