Ralph W. Dexter

• Biography
• Contributions of the Salem group of Agassiz zoologists to natural science education
• Edward S. Morse as a zoological illustrator
• From Penikese to the Marine Biological Laboratory at Woods Hole
• Historical aspects of Louis Agassiz's lectures on the nature of the species
• Historical aspects of studies on the Brachiopoda
• Historical aspects of systematic studies on sponges
• Peabody Academy's Caleb Cooke, the devoted
• The "Salem secession" of Agassiz zoologists
• The Essex County Natural History Society, 1833-1848
• The role of F. W. Putnam in founding the Field Museum
• The scientific period of the Cape Ann Scientific and Literary Association and its successors, 1873-1952