210 
PACIFIC SCIENCE, Vol. IV, July, 1950 
the species was first described, and Lucas re- 
ported it from Lord Howe Island. 
In summary, then, a synthesis of the ac- 
cumulated knowledge concerning the general 
morphology of Spongocladia reveals the fol- 
lowing features as most characteristic of the 
genus : 
1. The thallus is in the form of a pros- 
trate, spongiose growth, which remains as a 
compact mass in S. neocaledonica or produces 
erect, branched, Codium- like processes in S. 
vaucheriaeformis and S. dichotoma. 
2. The thallus is composed of intertwin- 
ing, branched, septate filaments, with the 
cells arranged in a single series. 
3. The branches of the filaments are not 
separated by a cross wall at the point of junc- 
ture with the parent filament. 
4. Septation of the filaments is by segre- 
gative division. 
5. The filaments form attachment organs, 
or tenaculae, by means of which they anas- 
tomose with other filaments, forming a kind 
of network. 
6. Reproduction is by s warmers which 
are produced in the unmodified cells of the 
filaments. 
These characters, with the possible excep- 
tion of the first one listed above, indicate that 
Spongocladia Areschoug (1853) is identical 
with Cladophoropsis, a genus which was seg- 
regated from Siphonocladus Schmitz (1879) 
by Bprgesen in 1905. This conclusion is 
supported by my own observations (partic- 
ularly in regard to the absence of a cross wall 
at the point of attachment of the branches 
to the parent filaments) upon a species of 
Spongocladia (seemingly S. vaucheriaeformis ) 
from the Philippine Islands and by those of 
Bprgesen (1946, 1948) upon S. vaucheriae- 
formis from Mauritius. The agreement in 
the general appearance of the filaments com- 
posing the thallus in Spongocladia and Clado- 
phoropsis is shown in Figure la and h, re- 
spectively, which are reproductions of illus- 
trations by Bprgesen from material gathered 
in the type regions of the type species of the 
two genera. 
The observations of Bprgesen in this con- 
nection are especially significant inasmuch as 
they were made, not only upon topotype ma- 
terial of the type species of Spongocladia, but 
by the author of Cladophoropsis. In 1946 
(p. 17) he remarked: "According to my 
observations of the alga [S. vaucheriaeformis ] 
it seems to me very like Cladophoropsis, for 
instance, Cl. Zollingeri . . .” and in 1948 
(p. 24) he said, "the alga, being the biont 
of the sponge, is quite like that found in the 
formerly examined specimens, and thus in 
my opinion is a Cladophoropsis .” 
Seemingly, the only difference between 
Spongocladia and Cladophoropsis lies in the 
general habit of the two genera. In Clado- 
phoropsis the thalli are in the form of cush- 
ions, turfs, or tufts whereas in two of the 
species of Spongocladia (S. vaucheriaeformis 
and S. dichotoma) the basal prostrate system 
ordinarily produces erect, Codium- like por- 
tions. However, these differences are not 
constant and appear to be of a specific rather 
than a generic nature. Support for this con- 
tention is furnished by two facts: (1) In 
S. neocaledonica the thallus is in the form of 
a compact, barely branched growth, some- 
what comparable to that of Cladophoropsis 
memhranacea ( Bprgesen, 1913: 43 and 47) 
and certain other species in which the thallus 
is in the form of dense cushions or turfs. 
(2) Even in S. vaucheriaeformis the thallus 
may at times, according to Bprgesen (1948: 
23), be in the form of an extensive prostrate 
mat, with the erect portions reduced to con- 
ical growths of only 2-3 cm. in height. 
Since the time that Bprgesen (1905) 
erected Cladophoropsis, and transferred to it 
seven species which had previously been 
placed in Siphonocladus, the genus has been 
found to be well represented in tropical and 
subtropical waters, and to contain a few spe- 
cies which are known only from temperate 
regions. A search through the literature re- 
