28 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY. 



old friend Mr. Isaac E. George, who suggested to me the influence 

 of the common lug-worm (Arenicola marina, Linn.) This animal 

 abounds on all the sandy and muddy stretches of our coast. Every- 

 where as the tide leaves bare the shore, its castings appear in 

 myriads. On sandbanks well to sea, where decaying matter is 

 scarce, Arenicola is found in small numbers, whereas along the 

 shore, especially in the higher littoral towards high-water mark, its 

 abundance is limitless. Here in Jersey is a region where after 

 storms, vegetable matter in the form of sea- weeds (Fucus, Laminar ia, 

 Chorda, &c), with a lesser though not inconsiderable amount of 

 animal debris, is piled up along the farthest tide-reached limits, 

 and a good portion of this soon becomes buried upon the beach. 



Now Arenicola in habits, is the marine counterpart of the 

 earth-worm. Like the latter, it is without any biting parts in the 

 mouth. It has no means of capturing prey, and contents itself with 

 swallowing the sand and mud it burrows in, extracting therefrom 

 what organic matter it can. Within limits then, the more putrefied 

 matter there is mixed with the mud and sand, the richer is the lug- 

 worm's diet. This explains how it abounds in more than common 

 number close to the outlets of rivers, in harbours and docks, and 

 also high upon the littoral — these places being where much decom- 

 posing matter" is deposited. Worm castings everywhere represent 

 the sand and mud passed out of the worm's body in a purified state, 

 freed from organic matter through such having been absorbed into 

 the nutritive fluid of the worm's body. 



Darwin astonished the world with his calculations of the magni- 

 tude of the cleansing operations carried on by the ordinary earth- 

 worm. On my part, I cannot give figures, but considering how 

 the castings of lug-worms are so numerous as practically to touch 

 one another ; that we see them renewed twice a day as the tide 

 uncovers the sands, and that such visible renewals represent not 

 one tenth of the work that goes on when the tide returns to give 

 more congenial conditions, we may be certain their workings over 

 areas of equal extent, are much more momentous than even those 

 of the earth-worm. It must, too, be borne in mind that the average 

 size of the lug-worm is greater than that of the earth-worm and 

 that on the average, though great, there is less organic matter in 

 sand and mud than in earth. Hence to obtain equal amount of food, 

 the lug-worm must swallow a much larger quantity of matter than 

 its land counterpart. As I have said, there is less organic matter 

 in littoral sand and mud than in earth, yet what there is, is infinitely 

 more evil smelling. The organic matter in earth is largely woody 

 fibre — slow of decay — and besides, as gases are evolved, such are lost 

 rapidly by diffusion in the atmosphere, to which the earth particles 



