Wells, Martin John. Lower animals [by] Martin Wells. - New York McGraw-Hill [1968] - 255 p. illus. (part col.) 19 cm. - World university library . Bibliography: p. [244]-249. LCCN: 68013140 Subjects--Topical Terms: Invertebrates LC Class. No.: QL362 / .W36 Dewey Class. No.: 592