Naturalist and zoologist whose work focused on invertebrates in the field of malacology. He did much of his most important work on freshwater mussels and crustaceans.
He studied at the University of Kiel and the University of Strasbourg.
He was the curator of invertebrate zoology at the Carnegie Museum in 1910.
He was born in Prussia and was a student of Ernst Haeckel.
He was a naturalist like Charles Darwin.