668 WATEK-ROLLED WEED-l^ALLS. — MACKAY. 



The last one in the third horizontal row is cut in two, but shows 

 nothino; in the centre different from the rest of the ball. 



These spe<2imens varied from sjjheres about five inches in 

 diameter to one and a half inches. Some were elona'ated. The 

 one o^i tlie ri<iht, in the u])i)er row, has a frond of Laiitoiai'ia 

 digitata Lamx. ])assi'ao' through the centi-e of the ball in its 

 longest directibn, and has in addition at its opposite polar 

 extremities, Dictijosiphoti fceiiinildcPiiSi Grev. growing on a 

 fragment of a waterworn clam shell, and other similar filamen- 

 tons branching alga*, not woi'u off', as thev are in the compact 

 oqnatorial region. A little more rolling in water over the Siand, 

 or by the wind (^ver the dry l>each, would likely soon wear oft' 

 the appendages down to a compact s])hei'oid. 



Some of the balls contain the roots of one of the larger sea- 

 weeds within them, one a mass of Corallina oJjUclndlls L. Others 

 contain embedded in them, various red sea-weeds, and even 

 masses of marine sponges. But they appear to be built up 

 mostly of the filamentous and fine branching olive brown alga\ 

 such as Dicti/osiiplioii. Dps))iar('sfia. Ecfocarjnis. CJiordnria and 

 ('li(,rda. with specime'as of nearly every other local speci'es of 

 seaweed, i'licluding material to which th:'y were attached 

 when growing, or with which ihey might become entangled 

 v.hen nuissing into l)aills. 



Their structure in the different forms examined suggest 

 their formation from light ridges of alga' left by the retreating 

 tide on the flat sandy shalloAvs. Trader the sun the weeds curl 

 and lock into masses which, when moved over the sand by alter- 

 nate tides and winds, occasionally ])roduce very round balls. 

 It would a])]K'ai- that the filamentous and fiae branching olive- 

 brown alga' are more brittle than many of the I'cd spepies which 

 are often found like the lai'gcr olivi' alga', extending lieyond 

 the general contotir of the i-olling lyall. 



Mr. Harry Piers, curator <d' the Provincial ^Tuseum, has 

 received a similar ball, collected bv Mr. J. Perrin, from the 



