THE DEVELOPMENT OF ELECTRA CRUSTULENTA (PALLAS) 265
1959 and 1960 two species, E. crustulenta and Membranipora
seurati (Canu), were growing abundantly there. I agree with Borg
(1931: 21) in regarding M. apiculata, M. seurati and M. fluviatilis,
all described by Canu (1928: 262-263, under Nitscheina) as
synonymous. The name Membranipora apiculata (Canu) is pre-
occupied by M. spiculata Canu & Bassler (1923: 21). I therefore
propose to adopt the name Membranipora seurati for the species
discussed here.
E. crustulenta and M. seurati are superficially very similar
and their colonies were completely intermingled on the weed in
the Creek. When Howes identified his material, M. seurati was
generally regarded as a Mediterranean variety of E. crustulenta
(see Borg, 1931: 22), and some of its most distinctive features
had not been noted. It has since been recognized (Hastings MS)
that M. seurati is specifically and, according to present classifica-
tion, generically distinct from E. crustulenta, and that its distribu-
tion extends to Britain and other northern European countries.
It would be interesting to know whether Howes's material in-
cluded both species. I am grateful to Dr. Howes and Professor
Medawar for their response to requests for information as to the
whereabouts of the specimens, which unfortunately do not appear
to have been kept.
In 1959 and 1960 the two species were growing principally on
the stems and more rarely on the leaves of Ruppia maritima.
Where the weed was gathered (i.e. at the north-west end of the
Creek) the colonies of M. seurati were more numerous than those
of E. crustulenta. The colonies of the two species showed a
distinct difference in seasonal condition. Those of M. seurati
were encrusting (the species can assume an erect convoluted form)
and showed very little marginal budding and no trace of sexual
reproduction. Those of E. crustulenta were actively budding,
producing foliaceous expansions and occasionally growing over
the colonies of M. seurati; they were in full sexual reproduction.
The material collected by Mr. G. Duncan Waugh in March 1957
also consisted of E. crustulenta and M. seurati, and showed the
same forms of growth and difference in condition of the colonies.
Hastings (MS) had tentatively concluded from preserved
material that the season and manner of sexual reproduction of
M. seurati were different from those of E. crustulenta. The
observations made in 1959 and 1960 appear to support this
conclusion as far as the breeding season is concerned. The
breeding of M. seurati. has not yet been observed.
As all the Cyphonautes larvae in March 1957 (Waugh) and
March 1959 and 1960 were those of E. crustulenta, Howes's record
of abundant Cyphonautes in March 1934 and 1935 is almost
conclusive evidence that part, at least, of his material was true
E. crustulenta.