The evolution of the thalamocingulate division of the limbic system is implicated in three forms of family related behavior that distinguish the transition from reptiles to mammals. Observations on various species with different degrees of development of the 4 main areas of cingulate cortex have the potential of providing information about the respective areal functions. The current work focuses on the common American mole (Scalopus aquaticus) because (1) it is a member of the order of insectivores with features linking them to mammal-like reptiles (therasids) and primates; and (2) its visual deficiency is possibly associated with a poorly developed cingulate retrosplenial granular area (area 29 of M. Rose). As in other mammals, application of a stain of acetylcholinesterase has proved useful in defining the location and extent of the retrosplenial granular area, while a special silver stain has given additional details about its fiber architecture. The availability of moles for this study provided the opportunity to record vocalizations. Two additional vocalizations with sound spectrograms resembling a separation cry and chucks are described.
