Cells posses both oral cilia and rigid equatorial cirri. The thoracic crustacean appendages are modified into feather-like cirri. The prostomium often also has appendages such as palps and tentacles or cirri. Peristomium fused with the first body segment, with usually two pairs of tentacular cirri. The first body segment with 1-2 pairs tentacular cirri without aciculae. The main cirri emerge from sheaths which cohere into a single firm fleshy mass. A number of brown, filamentous cirri or feeding tentacles project from between the plates. At each node between the columnals there is a whorl of five cirri. A nautilus has cirri, but a squid has tentacles. In general, crinoids move to new locations by crawling, using the cirri as legs. Whale barnacles passively filter food, using tentacle-like cirri, as the host swims through the water. However, the cirri do have a special function during copulation. The sides are ornamented with short cirri. The blunt heads of blenniiformids often possess elaborate whisker-like structures called cirri. In cirrate octopods suckers and cirri run and alternate on the entire length.