Ninespine stickleback Ninespine stickleback The ninespine stickleback ("Pungitius pungitius"), also called the ten-spined stickleback, is a freshwater species of fish in the family Gasterosteidae that inhabits temperate waters. It is widely but locally distributed throughout Eurasia and North America. Despite its name, the number of spines can vary from 8 to 12. The body of the ninespine stickleback tapers to a very narrow caudal peduncle and the caudal fin is fan-shaped. The body is less deep and more elongated than that of the three-spined stickleback with a thinner and longer caudal peduncle, but the best way of distinguishing these two species is
Operculum (gastropod) seals the shell, it can also serve as a protection against predators when the snail body is retracted. In life, the operculum is attached at the ending of the columellar muscle with an opercular disc dorsally to the upper surface of the posterior part of the foot. However, in "Buccinum" a layer of long cylindrical epithelial cells, with mostly distinct nuclei, and long divided processes enter between the muscular fibres. The operculum, a cuticular development of these cells, is composed, as may be seen in the corneous opercula of "Murex", "Purpura", "Triton", of very thin superimposed layers. The cylindrical cells