The Gray-Reptilian entity appears to be a cross breed between the Gray species and the Reptilian species.  [They have large heads.  In the drawing above, note the mandible-like formation around the mouth and the ridges over the eyes and along the skull.  Also note the 4 webbed fingers as opposed to 3 in the less complex species.   The Reptilians have created these half-breeds to serve as a slave race within their own culture. They are used as biological war machines, laborers, and have been involved in the abduction of Humans while the Reptilians observe from a distance.
The Gray-Reptilian species has the following characteristics: Between 3 to 5 feet in height, erect standing biped, small tin build, head larger than humans, absence of auditory lobes (external), absence of body hair, large tear-shaped eyes (slanted approximately 35 degrees) which are opaque black with vertical slit pupils, arms resembling praying mantis (normal attitude) which reach to the knees, long hands with small palm, claw-like fingers (various number of digits-often two short digits and two long-but some species have three or four fingers), tough gray skin which is Reptilian in texture, small feet with four small claw-like toes, organs that are similar to human organs but have obviously developed according to a different evolutionary process; a non-functioning digestive system; two separate brains; movement is deliberate, slow and precise.  The two separate brains are separated by mid-cranial lateral bone (anterior and posterior brain).  There is no apparent connection between the two.