332 University of Calif ornla Puhlications in Zoology. [Vol.8 



diameter and 1 cm. in height at lowest elevation with wire at its 

 lip. Over this wire a silk window (s. w.) is stretched tightly and 

 tied in place by a string (str.) behind the wire. This window 

 affords sufficient filtration surface to reduce an ordinary catch 

 to a volume readily contained by the detachable part of the 

 bucket, and, when worn, the silk is readily replaced. 



The weight (pi. 23, figs. 3 and 4) is flatiron-shaped, with 

 pointed end anterior, to reduce resistance in towing. It serves 

 as a foot for the net in landing on shipboard and may be removed 

 easily if not needed, as in shallow waters. Its weight is 40 kilos, 

 and it is made of cast iron. The spreading flange on its upper 

 surface fits into the recessed groove on the under surface of the 

 foot of the frame. It may be similarly grooved for a second 

 weight on its under face if desired. 



The total weight of the first model constructed, which differed 

 from the one here described principally in certain minor details 

 of construction and in the form of the frame and its weight, was 

 over 125 kilos. The present model without weight or messengers 

 Aveighs 70 kilos, with messengers 82 kilos. The cost of the im- 

 proved model, which necessarily included some experimental 

 work, and new patterns in large part, was three hundred and 

 twenty dollars, complete with messengers, silk net and bucket. 

 The apparatus was made by the Baker ^Machine Company of 

 8an Diego, California. 



METHOD OF OPEEATION 

 The setting up of the net for use is accomplished by fastening 

 the silli bag in place with the inner brass bands and tying the 

 closing strings around the pulleys. The supporting rod is 

 adjusted to the bucket and the weight slipped into the foot. The 

 springs are then adjusted to the proper degree of tension to 

 insure closure on release by the trips. The adjustment is made 

 by a square headed key which is inserted in the aperture at the 

 end of the hub and fitted into the recess (sock., pi. 24, fig. 9) at 

 the end of this axis (ax., pi. 24, fig. 5). The set screw at the 

 rear of the hub {s. scr., pi. 24, fig. 6 ; pi. 23, fig. 4) being released, 

 the spring is wound up and the axis secured in the desired place 

 by screwing in the set screws. It has been found empirically that 



