Capybaras have slightly webbed feet and vestigial tails. The hind wings are much smaller than the forewings and may be vestigial or absent. These are sometimes described as vestigial remnants of penile spines. The hind legs are enclosed inside the body, and are thought to be vestigial organs. There are two pairs of unbranched antennae, the first pair being vestigial in land-dwelling species. A case of vestigial organs was described in polyopisthocotylean Monogeneans (parasitic flatworms). They have bifurcated tongues and vestigial tail stumps. Some species have vestigial tails or no tails at all. It is not known if these organs are functional or simply vestigial. For the greater part Organs which may be rightly termed Vestigial. The maxillary palpi are reduced or even vestigial. Adults have vestigial mouthparts and do not feed. Some carnivorous animals may have appendices too, but seldom have more than vestigial caeca. All had small fore limbs, which seem to have been vestigial. The cryptomonad and chlorarachniophyte algae may contain a nucleomorph that resembles a vestigial eukaryotic nucleus.