[23] INSTEUCTIONS FOR COLLECTING MOLLUSKS BALL. 



convenient for the larger species; a knapsack of painted canvas being 

 best, as fluids do not leak out of it. A hammer, or small i)ick and 

 hammer combined, is frequently useful to crack rocks or coral for 

 pholads, or rake the gravel for hidden gastropods. To dig out living 

 bivalves a spade and a good deal of energy are required ; such collect- 

 ing is best made the subject of a special excursion. On the Pacific 

 coast a small rod of three-eighths inch iron, hammered to a chisel-shape 

 at one end and to a point at the other, is very useful in detaching Ralio- 

 tis, or large chitons, from the rock. If the blow is sharp and unex- 

 pected the mollusk will usually fall without injury, and in many j)laces 

 a small dip net will be of use for securing it. But if the mollusk is irri- 

 tated or disturbed before the collector strikes in earnest, it is better to 

 pass on, for the creatures when aroused will hardly be detached without 

 injury, so effective is their hold on the rock. The same is true to a 

 minor degree of the limpets. If chitons are collected they should be 

 placed on a narrow strip of smooth wood like a ruler, well wetted with 

 salt water, before they have time to curl up. By putting them oppo- 

 site one another and tightly winding soft twine, list, or lamp-wicking 

 around both chitons and stick, they will be kept in a normal posture 

 nntil the tissues are relaxed and they can then be preserved in spirits 

 or cleaned. If this precaution is not taken they are apt to curl up in a 

 shape which renders them almost useless for dissection or for cabinet 

 specimens and they will break rather than flatten out. A large number 

 may be set on a single stick. If, however, they curl before they can be 

 set, it is best to put them in a pan of salt water when they will, if alive, 

 eventually resume a normal position. A small sieve, with meshes of 

 one-sixteenth Df an inch, is often useful for sifting the sand out of drift 

 material which collects at high water and along the ripple marks. This 

 can be put in a bag or bottle and picked over at home. It is often very 

 rich in small species. An old table knife is useful for detachjng limpets 

 or chitons from smooth rocks. The dip net, if the frame is solid and the 

 meshes small, may be used to dredge out small bivalves from the loose 

 sand near low-water mark or from the soft mud of marshy shores. 



FAVORABLE LOCALITIES FOR SHORE COLLECTING. 



In the preceding remarks a statement of the special habitat preferred 

 by special groups has been embodied, and as conditions vary in differ- 

 tjut regions, the collector will find experience the best teacher in seeking 

 favorable spots for his work. It may be said, however, that the richest 

 fauna is likely to occur where a combination of varied elements con- 

 stitutes the shore. A beach composed of a mixture of mud, sand, and 

 gravel, or of mud and sand diversified by projecting rocks is always 

 more fruitful in species than a stretch of exclusively sandy, rocky, or 

 muddy shore. This is partly because of the varied conditions which 

 suit a larger variety of mollusks, and partly because the same diversity 

 of bottom promotes the multiphcation of the organisms which serve the 

 mollusks for food. 



