148 HOW TO WORK 



means of the pipette after each haul, and placed together in one tube, 

 especial care being taken that no larvas, likely to devour the specimens, 

 be accidentally placed among them. To provide against collecting 

 too many of the same species, it is as well to examine portions taken 

 from questionable hauls by means of the waistcoat pocket microscope, 

 designed by Mr. Highley, and figured in pi. VIII, fig. 37. In some 

 cases a pocket lens may be employed. The inconvenience of holding 

 the head upwards to the light in using the lens may be avoided by 

 placing the object on a reflecting prism, as suggested by Mr. Becker. 

 This idea has been further carried- out by Mr. Highley in his reflecting 

 live cage, fig. 225, which consists of a plate of brass having an aperture 

 into which a piece of thin glass is cemented, fitting by spring sides 

 on to a rectangular prism, so as to permit varying degrees of pres- 

 sure upon an object, or drop of water placed between the two glass 

 surfaces. The top surface of the prism being held horizontally, or 

 nearly so, light is projected from the reflecting plane of the prism 

 through the object to the eye ; Mr. Highley has adopted for this 

 arrangement a form of lens giving a larger field of view in relation to 

 the magnifying power than the ordinary Coddington lens. 



The implements already described are also employed for shore 

 collecting; but for the purpose of removing objects attached to 

 rocks, or the sides or bottoms of rock basins, a flat-faced geologist's 

 trimming hammer and a cold chisel should be added. 



For sea collecting, the surface net, the drag/look, and the dredge 

 are employed. 



The surface net is a double conical bag made of " cheese net," or 

 " bunting," stretched upon a cane hoop, and supported by three 

 pieces of cord, brought together at the point at which the towing 

 cord is attached. The inner cone is more obtuse and shorter than 

 the outer, and prevents objects once caught from being washed out 

 again. At the bottom of the bag is fixed a glass bottle, and a bung 

 is attached about a foot above it, to prevent it from sinking too deep. 

 Mr. Highley likewise advises that corks should be so placed at the 

 mouth of the hoop as to insure the net being only half immersed, 

 and the hoop being pulled into an oval form, so as to present a wider 

 mouth to the waves than when left circular. This net is towed 

 astern or at the side in such a way as to be clear of the boat's or 

 ship's wake, and the length of line is regulated to the strain created 

 by the speed of the vessel. On drawing up the net, the bottle is thrust 

 up through the hole in the inner cone, and its contents emptied into 

 a bottle of similar size, with a screw cap, of which some dozen 

 should be kept in a tray. Many interesting forms of Crustacea, 

 acalephas, medusa?, &c., can only be secured by this means. 



