1909] Ganong,— On Balls of Vegetable Matter 151 
Weed-Balls," Dr. A. H. MacKay describes fully, with photo-illustra- 
tions, some typical balls from the coast of Nova Soctia, and finds them 
composed of Algae, mainly Dictyosiphon, Desmarestia, Ectocarpus, 
Chordaria, and Chorda, with some other accessory materials (Pro- 
ceedings and Transactions of the Nova Scotian Institute of Science, 11, 
part 4, 1908, 667). Professor Farlow writes me that such balls occur 
also on the coast of New England. 
I find also, by the way, that in the former article I did not do justice 
to one of the references given by J. Adams in Science (19, 1904, 926); 
for his note clearly points to the occurrence of the balls in a lake of the 
Hebrides. Another, material unstated, is reported from a Nova 
Scotia lake by Dr. MacKay in the article above cited. And Professor 
Barrows, in the letter next to be quoted, mentions the occurrence of 
balls composed of tamarack leaves, in a lake in Oakland County, 
Michigan. 
Finally another, and very different, composition for balls of exactly 
similar mode of formation has been communicated to me by Professor 
Walter B. Barrows of the Michigan Agricultural College, along with 
several specimens. The balls are composed almost wholly of hair, 
and their origin is thus described in Professor Barrows’ letter (of Oct. 
7, 1908). 
The hair comes from a tannery located on the shore of Lake Michi- 
gan, a mile or two north of Petoskey, at a point called Kegomic, and 
these hair balls are cast up on the beach about a mile further along, 
although a few are found at other places around the bay. This beach 
forms the easternmost point of Little Traverse Bay апа receives the 
full force of the westerly and southwesterly winds, so that there is 
often a rather heavy surf on the beach. The hair balls are of all sizes 
up to at least five inches in diameter, although my recollection is that 
balls of that size are much less common than smaller ones. The shape 
also 1s quite variable but there seems to be a marked tendency towards 
elliptical outlines, so that the smaller ones often resemble cocoons 
quite closely. I am told by people living at Harbor Springs and at 
Petoskey that these hair balls have been a constant feature of the beach 
for fifteen or twenty years past, and presumably ever since the tannery 
was started. 
The wave-formed balls, therefore, occur in the sea as well as the lakes 
of fresh water, and they are made up of the most diverse materials. 
The one feature they have in common is their mode of formation, which 
depends upon the rolling action of the submersed parts of waves 
working upon fibrous substances resting lightly upon sandy bottoms. 
