METHODS OF COLLECTING AND PHOTOGRAPHING 69 



two inches long and may, by altering the dimensions, be cut out 

 according to the directions given for the townet. It should be 

 faced with strong muslin for two or three inches at each end. It 

 is tied by its upper end over the flange on the body. 



D. The screw tip consists of the screw top of a kerosene oil can, 

 extended by soldering to the male screw a copper cylinder an inch 

 and a quarter long. The cy Under is wired at its top to form a 

 projecting flange over which the tip of the net is tied. The cap 

 is weighted by soldering to it a lead ring of about two ounces. 

 Two loops of wire soldered to the outside of the screw tip serve for 

 the attachment of cords from the loops on the body and these 

 support the weight of the screw tip and take the strain off the 

 net. 



This net may be readily dragged behind a boat among dense 

 water plants by means of a cord attached to the eye. The cone 

 fends off the water plants and lessens the amount of debris entering 

 the net and clogging it. The net may also be thrown from shore 

 to a distance of thirty or forty feet and safely hauled back through 

 thick vegetation. It may also be run at some depth or along the 

 bottom by attaching a suitable weight to the line, two or three feet 

 in front of the cone. 



When a haul has been made the screw cap is removed so that 

 the contents of the net fall into a cup or jar of water. Several 

 successive hauls may be united. When the foreign matter which 

 always enters the net has settled to the bottom of the jar, the clear 

 water containing the entomostraca is poured into a metal funnel 

 with a long neck made of brass wire gauze of about forty meshes to 

 the inch (Fig. 12). The neck, which serves as a filter, terminates 

 in a tin ring which is corked. When the entomostraca have been 

 filtered from the water, the cork is removed and the catch washed 

 into an eight-dram homeopathic vial, short form, in which it is 

 preserved. 



When many catches from different localities are to be kept sep- 

 arate, Professor Birge uses flat bags, one by three inches, made by 

 stitching together on the sewing machine pieces of India linen. 

 Before going into the field the bags are numbered and strung on 

 a thread so that they may be pulled off in order. The catch is 



