Morphometric analysis of Aphrocallistes vastus.

Numbers represent means of 3–50 measurements from 1–8 samples. Percent of the inhalant surface, water velocity, and head losses (ΔH) at each region are compared with the ‘standard sponge’ of Riisgård et al. [30] and Larsen and Riisgård [29] (blue font) which are calculated using measurements made by Reiswig (1975). Regions and their dimensions (e.g., diameter and length) are identified by letters repeated in Figures 6 and 7. The sum of consecutive path lengths gives the distance (µm) from the surface of the sponge. The water velocity at each region is calculated for 10°C water and an excurrent velocity of 1 cm s−1 measured at the osculum, corresponding to a specific pumping rate of 3.1 mL (mL sponge)−1 min−1 (see text and Riisgård et al., 1993). ‘Atrial cavity’ and ‘Osculum’ pertain to the average size of the sponges used in the tank experiment (Table 1).The cross sectional area, water velocity and head loss of the passages through the aquiferous system in 100 ul (100 mm3) pieces.