Ranchu tail. The caudal peduncle itself should be broad and neither lengthy or too short (a properly formed caudal peduncle avoids swimming motion impairments to this type of goldfish). The ranchu's tail meets the caudal peduncle at a forty-five degree angle, giving the fish a unique swimming motion. Furthermore, the tail lobes are rounded, and all other finnage are paired. The most prominent feature of the ranchu is its head. There must be sufficient space between the eyes, and also from the eyes to the front of the head. The gill cover should figuratively extend quite far towards the tail. The
Operculum (gastropod) are attached with their head to the lowermost layer. The operculum grows in size as the shell grows, such that the operculum remains in proportion to the apertural size. In many species, when the animal is active and crawling, part of the underside of the shell rests on the outer surface of the operculum. In many species of marine shelled snails which live subtidally, the operculum is greatly reduced in size, and no longer serves to seal the shell entrance. In a large number of families it has been eliminated completely. In species of conchs, the operculum is elongated and