square shoulders (flat at the top of the whorls) and almost ° sutures. the shell opening (aperture) is large and oval, the umbilicus is large and deep. the size of the shell varies from - mm wide and - mm high. the spire is high and sharp, hance the often used name: spike-topped apple snail. the colour...
. when an irritant, such as a grain of sand, intrudes into the shell of the mussel and the mantle, or the interior of the mantle, the mussel coats the irritant with layers of the same substance that is used to create the shell. mother-of-pearl (nacre) which is mainly calcium carbonate and an organic...
the water. the eggs come out of the snail's body, one by one in a long string that folds up in such way that the eggs are attached to each other in one clutch. at this stage the eggs are small and have a white, translucent appearance. marisa cornuarietis depositing the eggs. day the eggs slowly enlarge...
part of the normal behaviour ( pomacea canaliculata ). breathing marisa cornuarietis . note the short siphon in this species. marisa cornuarietis with the penis sheath extended after mating. an years old pomacea diffusa with eroded shell . crawling pomacea diffusa . except where otherwise noted, this...