Sponges of Kaneohe Bay — DE LAUBENFELS 
31 
often it is about half this size. The interior 
is regularly ochre-yellow. The exterior is ex- 
tremely pale, almost white for specimens that 
grow in the shade, but a mahogany-brown 
for specimens which grow in relatively bright 
illumination. This was true of most of the 
Moku O Loe specimens. Among the brown 
tethyas, however, were a few that in life 
appeared black. In alcohol these promptly 
bleached to about the brown color that the 
others had in life, but the brown ones in 
alcohol bleached very pale indeed. The black 
specimens had identical spiculation, and in 
all respects, save for color, appeared to be 
identical with the brown ones. No difference 
in their ecological placement could be found 
to account for the difference in hue. The 
hypothesis here favored is that the black ones 
had a symbiont of some sort in or on their 
dermis, which symbiont was lacking from 
the brown tethyas. The consistency of this 
sponge is cartilaginous. 
The surface of Tethya changes with the 
reproductive cycle, but is always more or less 
verrucose. The protrusions are at the distal 
terminations of spicular fascicles, and are 
about 2 mm. in diameter. Their height varies 
during the reproductive cycle from nearly 0 
to more than 3 mm. so that they may actually 
depart from the parent as slowly motile buds. 
The pores and oscules are very contractile 
but the latter may open to as much as 2 mm. 
in diameter. There is seldom more than one 
oscule per sponge, and it is usually apical. 
Schmidt’s name diploderma is well de- 
served by the remarkable ectosome of this 
sponge. The outer cortex is about 650 g 
thick, and may contain symbionts, reproduc- 
tive tissue, and protective tissue including 
microscleres. The inner cortex is about as 
thick or a little thicker, is pale, full of strong 
smooth muscle tissue, and very contractile. 
Not only may the pores and oscules be 
closed promptly, but the whole sponge seems 
to grow smaller when these muscle fibers 
contract. 
The endosome is rather dense, and is per- 
meated by radiating columns or tracts of 
megascleres; each tract is about 200 g in 
diameter. There is one column for each 
dermal protrusion. 
Fig. 20. Tethya diploderma, spicules, from a 
camera lucida drawing, X 333. A, style or fusi- 
form strongyle. B, spheraster. C, small tylasters, 
common shape. D, euaster, less common shape. 
The megascleres are inequiended, fusiform 
strongyles. The small end is usually pointed 
toward the surface of the sponge and is so 
small that the spicule almost becomes a style. 
Indeed, some actually appear to be genuine 
styles. They range in size from 8 by 500 g 
up to at least 20 by 1500 and 25 by 1250 g. 
There are two sorts of microscleres. First, 
there are large spherasters, 25 to 75 g in 
diameter, more often near the larger size. 
These are chiefly localized just under the 
cortex. Second, there are myriads of small 
tylasters with microspined rays. The total 
diameter of the asters is only 5 to 11 g. They 
are abundant both in the outer cortex and 
throughout the endosome. 
This species was first described by Schmidt 
(1870: 52) from the West Indies, but has 
since been shown, especially by Burton 
(1924: 1039), to be practically cosmopoli- 
tan. A very interesting article by Edmondson 
(1946: 271 and following) discusses the 
asexual reproduction of this species as it oc- 
curs in Hawaii, but uses the name Donatia 
deformis. The name Donatia is a later syn- 
onym for Tethya but was used for a while 
on the unwarranted assumption that the still 
earlier name Tethys (for a mollusk) pre- 
occupied Lamarck’s (1814: 69) establish- 
ment of Tethya. The two names are, of 
course, quite different. The species deformis 
