166 
PACIFIC SCIENCE, Vol. XIX, April 1965 
TABLE 6 
:haracteristics 
M. maunaloa 
M. eurypa 
Large styles 
425 X 13m (and up) 
287-490 X 7.5-1 3m 
Ectosomal styles 
120-160 X 6m 
(scattered spicules 240 X 9 m) 
112-237 X 3.5-5M 
Acanthostyles 
42 X 8m 
80-106 X4-6.5M 
Large isochelae 
14m 
13.5-1 8m 
Small isochelae 
5 -6m 
3.5-5m 
Toxa 
56-132m 
36-181M 
Color in life 
caramel-brown 
coffee 
Rhaphidophlus cervicornis Thiele, 1903, p. 
959, pi. 28, fig. 24. 
Rhaphidophlus cervicornis Brpndsted, 1934, 
p. 22. 
Thalysias cervicornis de Laubenfels, 1954, p. 
135, fig. 86. 
OCCURRENCE: Sta. 220B. 
DESCRIPTION : Several fragments of this 
sponge were collected and all are probably part 
of one colony. The habit is ramose, with irreg- 
ularly disposed branches, 0.7-1. 0 cm in diame- 
ter, in many cases reduced to short nodules, 
arising from a repent base which produces 
numerous short processes at right angles to 
its long axis. 
COLOR: In alcohol, pale brown to gray 
(Y-RY 7/2) to (Y-R-Y 7/5) for the ecto- 
some, mid-brown for the endosome (yY-R 4/4). 
TEXTURE: The ectosome is soft and easily 
torn; the endosome is stiff and incompressible. 
SURFACE: Macroscopically smooth, marked 
by ramifying subdermal canals. Under low mag- 
nification numerous dermal spicule tufts are 
visible and render the surface minutely hispid. 
Only two oscules are visible, 0.5 and 0.8 mm in 
diameter, situated on the main stem at the junc- 
tion of a branch. 
SKELETON: The spiculation and the arrange- 
ment of the skeleton are entirely typical of 
Rhaphidophlus as redefined by Levi (I960). A 
compact, fibrous endosome of plumoreticulate 
pattern is invested by an ectosome of compara- 
tively fleshy nature supported by special ecto- 
somal spicule brushes which are most pro- 
nounced in the subdermal position. 
The endosomal fibres are cored in their cen- 
tral third by smooth subtylostyles often having 
asymmetric heads. Short acanthostyles echinate 
the fibres. Interstitial subtylostyles are abun- 
dant and are in no way distinct from the cor- 
ing spicules or from the bulk of the ectosomal 
spicules. The subtylostyles making up the sur- 
face brushes tend to be finer and smaller than 
the interstitial spicules. 
Endosomal spongin fibres are 70-350/* in 
diameter, with frequent anastomoses and little 
soft tissue remaining between them. The ecto- 
some is 0. 1-0.2 cm wide, supported chiefly by 
obliquely disposed bundles of subtylostyles and, 
at intervals, by short lateral branches from the ; 
endosomal fibres. These fibres never extend to | 
the surface of the sponge. In the superficial re- I 
gion of the ectosome the spicules are of a j 
slightly different type, grouped into brushes J 
oriented at right angles to the sponge surface. . 
These dermal brushes arise from a region 125- ! 
300/* below the sponge surface and fan out j 
externally to a diameter of 200-350/*. Between j 
the bases of the brushes is a zone of subdermal 
cavities overlain by the dermal membrane. 
SPICULES: Megascleres. (i) Coring and in- 
terstitial subtylostyles, slender, slightly wavy j: 
or curved in the proximal third, with frequently 
asymmetric heads; 262-325 X 4. 5-6.0/* (291 1 
X 5.0/*). 
( ii ) Echinating acanthostyles, often with 
subtylote heads and clear of spines in the proxi- 
mal half of the shaft; 50-62 X 4.5— 6.5/* (57 
X 5.7/*). 
(iii) Auxiliary dermal subtylostyles; 95-132 
X 3.0-45/* (109 X 3.8/*). 
