  We investigate the physical properties of high-quality single crystals CeGaGe
and PrGaGe using magnetization, heat capacity, and magnetotransport
measurements. Gallium-indium binary flux was used to grow these single crystals
that crystallize in a body-centered tetragonal structure. Magnetic
susceptibility data reveal a magnetic phase transition around 6.0 and 19.4 K in
CeGaGe and PrGaGe, respectively, which is further confirmed by heat capacity
and electrical resistivity data. A number of additional anomalies have been
observed below the ordering temperature in the magnetic susceptibility data,
indicating a complex magnetic structure. The magnetic measurements also reveal
a strong magnetocrystalline anisotropy in both compounds. Our detailed analysis
of the crystalline electric field (CEF) effect as observed in magnetic
susceptibility and heat capacity data suggests that the $J$ = 5/2 multiplet of
CeGaGe splits into three doublets, while the $J$ = 4 degenerate ground state of
PrGaGe splits into five singlets and two doublets. The estimated energy levels
from the CEF analysis are consistent with the magnetic entropy.
