On the identity of the “Cotton Spinner” (Holothuria nigra) of English authors with Holothuria Forskalii, Chiaje, and on the occurrence of Cucumaria Koellikeri, Semp., in the Atlantic Ocean

On the identity of the “Cotton Spinner” (Holothuria nigra) of English authors with Holothuria Forskalii, Chiaje, and on the occurrence of Cucumaria Koellikeri, Semp., in the Atlantic Ocean