THE SPONGES OF THE WEST-CENTRAL PACIFIC 7 



U.S.N.M. No. 22884, My No. M. 184, with the same collection data as the 



preceding - . 

 U.S.N.M. No. 23056, My No. M. 436, collected on August 1, 1949, by hand 

 while wading in eastern Ponape (Matalanim) near the great ruins of 

 Nan Matal. The depth was barely below low tide, and the substrate 

 was a combination of calcareous sand and leaves of a monocot plant 

 called "turtle grass." 

 U.S.N.M. No. 23098, My No. M. 480, collected on September 1, 1949, by 

 divers in the Palau archipelago in Iwayama Bay, near Koror. The 

 depth was 2 meters, and the substrate was small bits of dead coral. 

 U.S.N.M. No. 23135, My No. 518, collected on September 8, 1949, while 

 wading on the west shore of Babeldaub Island, in a bay 5 kilometers 

 north of Ngeremetengel, in the Palau archipelago. The depth was 

 about 1 meter, and the substrate was broken bits of deal coral. 

 This species is certainly abundant in some portions of Ponape and the 

 Palaus. I believe it is equally common lear Lemotol Bay in the Truk region, 

 but the only sample which was collected as being presumably of this species 

 from Truk proved instead to be another species. Spongia zimocca as found 

 in Micronesia definitely prefers very shallow water (under 2 meters), even 

 where this water must surely become very warm (estimated 35° plus). It 

 thrives in water discolored by emanations from adjacent mangrove swamps, 

 and it endures more mud and silt in the water than do many other sponges. 

 The shape is basically massive, with large projections on the upper sur- 

 face. These may be lobate, but typically are elongate cones, each with an 

 apical oscular aperture; they may be more than 10 cm high, and the whole 

 sponge more than 15 cm high. Diameters (of the whole sponge) may 

 exceed 25 cm. 



The color of the exterior was regularly black, but that of the interior 

 varied; it might be orange or drab with portions shading into crimson, or 

 (often) drab with portions shading into rusty red. This species frequently 

 emits a typical Spongia odor, stronger than the preceding species, but quite 

 like the odor of many freshly collected Spongias from the West Indies. The 

 consistency was very spongy. 



The surface is conulose, with conules 1 mm high, or occasionally a little 

 less, and 1 to (usually) nearly 2 mm apart. The skeletal pores range from 

 about 100 fi to 200 /* diameter. Each such mesh is filled in with a proto- 

 plasmic membrane, pierced by 6 to 10 pores, which are closable and open to 

 a diameter of about 20 /x to 40 jx. The skeletal pores are about 300 /x apart, 

 center to center. The oscules are small and numerous. They range from 

 2 to 16 mm in diameter and often are only about 3 cm apart center to center. 

 In the lobate specimens they are found on the summits. In fact, it is worthy 

 of comment that they are found in general only on the upper surface of 

 the sponge. 



