146 G. T. HARRIS ON THE COLLECTION AND 



thoroughly sound in practice, and I always adopt it, carrying 

 a mackintosh sheet for the purpose. It should be recollected 

 that a superficial examination of any rock-pool is not sufficient 

 to detect minute species, and even species of considerable size, 

 such as Plumularia setacea, often harmonise so well with their 

 surroundings as to be difficult of detection. As far as possible 

 it is best to assume a comfortable position, and then thoroughly 

 examine the basin and the seaweeds it contains, using a lens of 

 about 4 inches diameter when necessary. Many rock-pools have 

 projecting ledges draped with fucus ; such are found to be espe- 

 cially prolific if well examined. The fucus should be turned 

 right back, so as to expose the sides it covered and the under 

 surface of the ledge, which are normally in deep shade. Sponges 

 growing underneath may be scraped off and examined for com- 

 mensal hydroids. If long, dark tunnels exist in the rock, the 

 arm should be pushed up and the upper surface of the rock felt 

 over with the hand for any adherent masses of sponge, etc., 

 which may be broken off and examined. This is a distinctly 

 sporting method, as it gives the crab, when there, a chance to 

 get in first with his pincers. Bring him out and hold him under 

 water in the rock-pool while you go over him carefully with a 

 lens ; his carapace will probably recompense you for the pinched 

 finger. Shells, also, should be carefully examined. The only 

 time I ever took Podocoryne areolata was upon a shell found lying 

 at the bottom of a funnel-shaped rock-pool, and Professor 

 Allman had the same experience. Many species are so minute 

 as to defy detection by the ordinary methods of shore collecting 

 and are best obtained by taking small tufts of seaweeds and 

 looking over them at home with the compound microscope. 



I have remarked previously that collecting is often very re- 

 munerative on shores strewn with large fucus-covered boulders. 

 Those who know Llandudno and Criccieth will recognise excellent 

 examples of such shores, and doubtless many similar exist round 

 the coast. The boulders near low-water mark yield the richer 

 harvest, and the underneath is the surface to work. Where 

 two of these huge boulders have fallen close together, so as to 

 form a miniature tunnel, the latter is sure to afford a prolific 

 hunting-ground. My method is to lie on my back and gradually 

 work into the tunnel, carrying a blunt knife and some fair-sized 

 bottles, or jars, of sea-water, The surface of the rock is chipped, 



