BVRI and H \alpha imaging and long–slit optical spectroscopic data are presented for four morphologically normal and relatively isolated Sa galaxies , NGC 3626 , NGC 3900 , NGC 4772 and NGC 5854 .
VLA \ion H1 synthesis imaging is presented for the first three objects .
In all four galaxies , evidence of kinematic decoupling of ionized gas components is found in the long–slit spectroscopic data ; the degree and circumstances of the distinct kinematics vary from complete counterrotation of all of the gas from all of the stars ( NGC 3626 ) to nuclear gas disks decoupled from the stars ( NGC 5854 ) to anomalous velocity central gas components ( NGC 3900 and NGC 4772 ) .
In the three objects mapped in \ion H1 , the neutral gas extends far beyond the optical radius , R _ { HI } / R _ { 25 } \geq 2 .
In general , the \ion H1 surface density is very low and the outer \ion H1 is patchy and asymmetric ( NGC 3900 ) or found in a distinct ring , exterior to the optical edge ( NGC 3626 and NGC 4772 ) .
While the overall \ion H1 velocity fields are dominated by circular motions , strong warps are suggested in the outer regions by bending of the minor axis isovelocity contours ( NGC 3900 ) and/or systematic shifts in position angle between inner and outer rings ( NGC 3626 and NGC 4772 ) .
In the interior , coincidence is found between the H \alpha and \ion H1 in rings , sometimes partial and crisscrossed by dustlanes .
Optical imaging is also presented for NGC 4138 previously reported by Jore et al . ( 1996 ) to show counterrotating stellar components .
The multiwavelength evidence is interpreted in terms of the kinematic “ memory ” of past minor mergers in objects that otherwise exhibit no morphological signs of interaction .

Key words : – galaxies : evolution – galaxies : individual ( NGC 3626 , NGC 3900 , NGC 4138 , NGC 4772 , NGC 5854 ) – galaxies : interactions – galaxies : kinematics and dynamics – galaxies : spiral