SEXUAL BEHAVIOR OF ALBINO RAT 103 



repeated licking and smelling in the ano-vaginal zone, scratching 

 his own body, and momentarily sniffing at the wires of the cage. 

 Rarely, at such times, he stops to lick the penis. The copulatory 

 act, when it does appear, comes with such definiteness and or- 

 derly sequence of elements that it stands out in marked contrast 

 and is never confused with this background of promiscuous activ- 

 ities. It is an organized unit of behavior that runs its course 

 with great smoothness when the first element of the series is set 

 into action. 



In the act of mounting, the male clasps the sides of the female 

 with his fore-paws encircling her body just posterior to the short 

 ribs. The palmar surfaces of the fore-paws are directed medial- 

 ward, in a dorso-lateral, lateral, or ventro-lateral position on the 

 female's sides, varying with the size of the female and the girth 

 of the male's fore-limbs. Simultaneously with the clasp, or 

 following so closely that no tune interval is discernible, rapid 

 vibratory palpation of the female's sides occurs. To the pal- 

 patation, the female responds by depressing the back deeply in 

 the lumbar region. This movement simultaneously elevates the 

 coccygeal region with the hip-joint serving as a fixed pivot of 

 rotation. The elevation of the coccygeal region raises the ex- 

 ternal orifice of the vagina from the floor of the cage to a height 

 more accessible to the male, and at the same time, throws the 

 axis of the vagina into a plane conforming with the direction of 

 piston movements of the penis when vaginal entrance is 

 attempted. 



Following the palpation of the female's sides, which serves 

 as an adequate stimulus for the depression of her back with 

 consequent elevation of the coccygeal region, the male makes a 

 series of rapid movements of the pelvic region which serve to 

 direct the erect penis into and out of the vagina in piston-like 

 manner. With the consummation of the orgasm the palpa- 

 tion and piston movements cease and the male throws himself 

 from the position assumed in mounting by a vigorous backward 

 lunge that clears his body from that of the female by a distance 

 of from three to five or more inches. With the backward lunge 

 he comes to a sitting position with the weight of the body sup- 



