Cardiapoda known only two species from worldwide.
C. richardi is smaller species than C. placenta.; the tail is long like a filamentous; gill handle is shorter than C. placenta. ; gill number is eight; shell is not characterized at old literature but, actually they has a very thin shell. Retractable brown, membranous structure on the mid ventral surface of the tail. Lens of eye rests in a surrounded in a U-shaped retina. Japanese name is "Muchio-Zoukurage". "Muchio" mean tail shapes filamentous. "Zou" mean an elephant. "Kurage" mean a jellyfish.
These pictures all took at Kume-Island Okinawa Japan. Size: about 35mm. This individual is female. Because egg strings is releasing from near the gill and Cardiapoda is known that fin sucker present only in males. Body is covered with many reddish pigment. There was a behavior to round the body. This is considered to be for defense. Brown membrane appeared only at that time. In normal posture the brown membrane is stored in the ventral surface of tail.
Lens of eye rests in a surrounded in a U-shaped retina.
Retractable brown, membranous structure on the mid ventral surface of the tail.
normal posture, brown membrane is stored in the ventral surface of tail.