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330 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
gcametangia, from which are derived swarmspores or 
gametes. 
Three species of Codiwm (out of fifteen) occur in British 
seas, but only one, C. tomentoswm, occurs in the L.M.B.C. 
district. 
CoDIUM. 
The genus Codiwm was first established by Stackhouse 
(Ner. Brit., 1795—1801), to receive the type previously 
known as Fucus tomentosus. This name the same 
authority altered to Lamarkea in the second edition of 
his work, and included under it two species C. tomentosum 
and the plant now known as C. bursa. Lamouroux, in 
1813, proposed the name Spongodiwm for the genus, 
whilst, later still, Cabrera re-christened these and other 
species by placing them in the newly constituted genus 
Agardiva. C. Agardh reverted to the name suggested by 
Stackhouse, and, at the same time, re-defined the genus. 
Decaisne subsequently sub-divided the then known species 
into two genera, one represented by Codiwm tomentosum, 
for which he retained the name of Codiuwm, the other 
represented by Codiwm bursa, to which he gave the name 
of Spongodium. 
An elaborate and authoritative account of the genus 
was, in 1885, published by the great Swedish Algologist, 
J. A. Agardh (Till Algernes Systematik, Lunds Univ. 
Arsskr., XXITI.). In this monograph he includes all 
previously known species under the single generic heading 
of Codiwm, sub-dividing them, however, into tribes, which 
are, on the whole, co-extensive with the genera established 
by preceding authors. 
The first tribe established by Agardh is that represented 
by Codium adherens, Cabr., where the thallus is firmly 
fixed to the substratum in the form of a dark green, gela- 
