4 THE MARINE ALGAE OF ESSEX.
by the presence of such distinctly southern forms as Grateloupia
filicina, Scinaia furcellata, Cutteria multifida, and Taonia atomaria,
while there is no admixture of characteristic northern species,6 so far
as we know.
A list of those species which may, with some degree of proba-
bility, be expected to occur on the Essex coast, is given at the end
of this paper.
SCHIZOPHYCEAE, Cohn.
MIXOPHYCEAE, Stizenb.
Chroococcaceae, Rab.
GLOEOCAPSA, Nag.
Gloeocapsa crepidinum, Thur., "Notes Alg.," i., p. 1. In
shallow rock-pools, and also on posts at or a little above high-water
mark. Southend, July, 1890, Mrs. T. H. Buffham, Clacton, Jan.,
1893, E. A. B.
APHANOCAPSA, Nag.
Aphanocapsa marina, Hansg., in "Foslie Contrib.," i., p. 169.
In shallow rock-pools, and on posts at high-water mark, usually
mixed with species of Calothrix and other small algae. Clacton,
Jan., 1893, E. A. B. Rare.
Chamaesiphonaceae, Borzi.
DERMOCARPA, Crouan.
Dermocarpa prasina, Bornet, "Notes Alg.," p. 73. On the
fronds of Rhodochorton rothii. Clacton, Jan., 1893, E. A B. Not
uncommon.
HYELLA, Bornet et Elahault.
Hyella caespitosa, Born. et Flah., in Morot, "Journal de
Botan.," ii., 1888, p. 162. Growing in the substance of old shells.
Clacton, Jan., 1893, E. A. B. Rare.
HORMOGONEAE, Thur.
HOMOCYSTEAE, Born. et Thur.
Lyngbyeae, Kutz.
SPIRULINA, Turp.
Spirulina subsalsa, OErsted, "Beretning om en Excursion til
6 Not them species do not, except very rarely, come further south than the north of Norfolk,
where Ptilota plumosa has been reported, but oh rather doubtful authority, from Cromer. Of
course the older records of the occurrence of "Ptilota plumosa" on the coast of Devonshire, etc.,
refers to "Plumaria elegans," which was formerly regarded as simply a form of Ptilota plumosa.