(Band 2): Mit hundert und sechs illuminirten Kupfertafeln
Esper's 1794 German natural history volume of 106 hand-coloured copper plates, held by Heidelberg University Library, documents sponges and related marine organisms for naturalists and scholars. The plates show branching, lobed and fan-shaped sponge forms in muted tans and browns, with small magnified detail roundels; a designer could draw on their organic silhouettes, stippled textures and tidy scientific plate layouts.
