Cassidulus caribaearum Lamarck 1801

Cassidulus cariboearum Lamarck

Cassidulus cariboearum Lamarck, 1801:549. [For a synonymy see Mortensen, 1948a:205.]

Frederick Hotchkiss found six live specimens of this species while screening the coarse sand that lies in one meter of water 5–10 meters from the shore on the northeast side of Carrie Bow Cay. This discovery is particularly important because this species has never been seen before alive in situ. Nothing was known for certain of its living habits. The species was known to range from a depth of 46 cm (Kier, 1962:21) to 197 m (Agassiz, 1872:343). Although Mortensen (1948a: 193, 209) reports that observations are lacking on living specimens, he predicted that it would be found living buried in coarse sand. As is so often the case with Mortensen’s predictions, he was correct. After Hotchkiss discovered the specimens, he placed them in a glass vial with some of the coarse sand; and within 3–4 minutes they had buried out of sight. The specimens reached a maximum depth of 3.4 cm suggesting that this may be their normal depth of burial. Hotchkiss found only six specimens after hours of digging through square meters of sand; therefore, the species does not occur in large numbers. Two dead tests that were washed up on the beach on Carrie Bow Cay were found in April 1974 by Miss Annie Bowman; but I found no specimens in four weeks of diving in 1973 and 1974.

Hotchkiss reports that the specimens were white when alive but turned green when placed in formaldehyde.