A comparison of the Eimer's organs of three north american moles: The hairy‐tailed mole ( Parascalops breweri ), the star‐nosed mole ( Condylura cristata ), and the eastern mole ( Scalopus aquaticus )

Eimer's organ is a tactile sensory structure found predominantly on the snouts of moles. It consists of a raised papilla of epidermis containing a column of cells associated with sensory receptors. This study compares the Eimer's organs of the hairy‐tailed mole, Parascalops breweri , the star‐nosed mole, Condylura cristata , and the eastern mole, Scalopus aquaticus , by using scanning electron microscopy and light microscopy. Eimer's organs are visible on the snout of the hairy‐tailed and the star‐nosed moles, but not the eastern mole. The Eimer's organs of the hairy‐tailed mole are similar in external appearance, distribution, and internal structure to those found in most species examined. The Eimer's organs of the star‐nosed mole and the eastern mole diverge from this basic form in seemingly opposite directions. The Eim&'s organs of the star‐nosed mole are more numerous, smaller, and highly organized units with a consistent pattern of neuronal terminal swellings within a cell column, below a thin keratinized epidermis. By contrast, the Eimer's organs ofthe eastern mole lie below a thick keratinized epidermis, are less organized in structure, and have no central cell column. The extreme differences between the Eimer's organs of the star‐nosed mole and those of the eastern mole may be the result of the habitat of each species, saturated mud allowing a more elaborate and delicate sensory apparatus in the star‐nosed mole and drier soil requiring a thick keratinized epidermis over the organ in the eastern mole. © 1995 Wiley‐Liss, Inc.