. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. SANDY LAGOON SPONGES 365. * Figure 2. Bicmna ehrenbergi in silu. (A) The chimney-like siphons, which are above the sediment surface. (B) The sponge after sediments have been removed. Arrows indicate sediment level. were of medium size, and less than 2% were smaller than 74 ^m (Table I). We found specimens of B. ehrenbergi buried to depths of up to 20 cm. with most of the body covered with sand (Fig. 2A). When the buried part was uncovered it was found to be attached to the beach-rock (Fig. 2B). More- over, the shape of the b
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. SANDY LAGOON SPONGES 365. * Figure 2. Bicmna ehrenbergi in silu. (A) The chimney-like siphons, which are above the sediment surface. (B) The sponge after sediments have been removed. Arrows indicate sediment level. were of medium size, and less than 2% were smaller than 74 ^m (Table I). We found specimens of B. ehrenbergi buried to depths of up to 20 cm. with most of the body covered with sand (Fig. 2A). When the buried part was uncovered it was found to be attached to the beach-rock (Fig. 2B). More- over, the shape of the buried part resembled a conus with a large base bearing several projections (Fig. 2B). Only these projections—the chimney-shaped siphons—ex- truded (1-7 cm) through the sediment (Fig. 2A). Oscula are located at the uppermost part of the siphons. The sponge is capable of closing its oscula, and thus probably is able to avoid intake of particles during storms. Observations, using dye injected above and into the sed- iment 10-15 cm from the siphons, revealed that most of the water pumped into the sponge came through the pores of the buried surfaces; only a minute amount was taken in by pores on the exposed surface of the siphons. Less than a minute after dye was injected into the sediment, it exited from the oscula in a strong flow; but when injected above the sediment surface, only a small amount of dye emerged from the oscula. Surface structure and morphology Most of the ostia (inhaling openings) are located on the upper surface of the body and are buried in the sed- iment (Fig. 3b). The exposed siphons are almost devoid of such openings (Fig. 3a). The average size of the oval pores is ± ^m, with a range of /urn (Fig. 3b). The ostia are transcellular, composed of a single cell (Fig. 3b). The total surface area of the buried parts is ex- tended through processes that protrude from the main central body. B. ehrenbergi has many small excurrent canals that are acc
Size: 1045px × 2393px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
