222 



THE SPONGES OF THE WEST-CENTRAL PACIFIC 



U.S.N.M. No. 23085, My No. M. 467, collected August 13, 1949, by diver 

 in Lemotol Bay in the western portion of Truk Lagoon. The depth was 

 4 meters, and the substrate was coral sand. 



It was amazing to note the lack of small specimens of this sponge. It 

 seemed to be characterized only by enormous individuals. The type specimen 

 was 33 cm high and 21 cm in diameter. Much larger ones were noticed in the 

 Truk region. They extended to a height of at least 45 cm and a diameter of at 

 least 57 cm, by actual measurement in the field. No specimens as small as a 

 human head were observed. The shape of the bulk of the body is more or less 

 spherical. A few specimens are wider than high, but more specimens are 

 higher than wide. In this, an enormous cloaca with its opening in the center of 

 the top of the sponge is conspicuous. This cloaca is often 4 cm in diameter 

 and 8 or 9 cm deep but much larger cloacas occur. Each has a conspicuous, 

 sharply delineated lining. On the lower side of the sponge, a number of roots 

 are in evidence. These are often 2 or even 3 cm in diameter and 10 to 15 cm 

 long. At the distal end, each branches into a number of short small subdivi- 

 sions. These roots ramify among the fragments of coral or the coral sand in 

 which the sponge grows and serve to give it ample support. There are usually 

 more than five, and sometimes as many as fifteen such roots per specimen. 



The color in life was in general an ochraceous brown, but the base and 

 part of the roots are more or less maroon. Some parts of the roots are 

 rather white, perhaps being moribund. The conspicuous cloacal lining is very 

 dark ochre in contrast to the somewhat lighter general surface. The interior 

 is very pale drab, but there is a subdermal layer of mahogany brown, about 

 1 mm below the actual surface and about 0.3 mm thick. This constitutes a 

 sharp separation between the ectosome and the endosome. The consistency 

 could be described as somewhat cork-like or wood-like. There was some 

 elasticity, but a good deal of stiffness. 



The surface is covered with low tubercles or knots about 1 cm high and 

 about 4 mm in diameter. These are from 1 cm to (less often) 2 cm apart. 

 In the valleys between them there are numerous conspicuous pores, 2 to 3 mm 





* ikv 



Text Figure No. 153. Spicules of Stellcttinopsis isis. A: Oxea, X 182; the entire spicule 



shows, but in two parts. B: Acanthoxea, X 782. C : Centrotylote acanthoxea, X 782. 



D: Two of the microspined oxyeuasters, X 782. 



