xiii, b, 6 Ruth: The Philippine House Lizard 313 



diameter of 8.3 millimeters on the right side, while the gland on 

 the left side has an average length of 7.3 millimeters. The 

 average lateral diameter was 6.3 millimeters. The calcium 

 glands of pregnant individuals of Peropus mutilatus are some- 

 what smaller, having an anteroposterior diameter of 5.4 milli- 

 meters and a lateral diameter of 4.2 millimeters. In all preg- 

 nant lizards where the egg substance was almost ready to receive 

 its calcium shell the gland was always found engorged with 

 calcium milk. In several instances after the shell had been com- 

 pletely formed and the eggs were ready to be laid the calcium 

 gland was found to be practically devoid of its calcium content. 

 When the gland is engorged with calcium milk, small, filled cana- 

 liculi are seen to communicate with the occipitoparietal sinus, 

 which also is filled with this milky fluid. The females in which 

 the eggs were not developed showed the same type of gland as 

 found in the male. All male lizards of this species that were 

 examined contained only a comparatively small amount of cal- 

 cium in the gland, while in a number there was no calcium 

 deposit whatever. In no instance was the gland found enlarged 

 and engorged as it was in the pregnant lizards. The average 

 anteroposterior diameter of the calcium gland in the male speci- 

 mens was 4 millimeters, while the lateral diameter was 3 milli- 

 meters. It is plainly evident that the functional activity of the 

 calcium gland is greatly increased during the period when the 

 calcium is secreted to form the shell about the egg substances. 



In Peropus mutilatus the gland is somewhat smaller than in 

 Cosmybotus platyurus. However, the same general conditions 

 obtain in this species as in Cosmybotus. The gland in the preg- 

 nant lizard is always large and is filled with amorphous calcium. 

 In the male the gland, in a large proportion of specimens, con- 

 tained no calcium deposit whatever. 



In both species the gland, when engorged, can be easily seen 

 lying underneath the skin. In Cosmybotus platyurus the gland 

 lies somewhat more superficially than in Peropus mutilatus. 

 When an effort is made to remove the skin of Cosmybotus, it 

 sometimes adheres firmly to the gland, so that the latter is broken. 

 In Peropus the gland lies more deeply — well below the superficial 

 fascia, and therefore the overlying skin and the gland never 

 adhere to each other. In both species the gland is well sur- 

 rounded by voluntary muscle fibers. 



The calcium glands were also studied in a large series of the 

 gecko (Gekko gecko), which is a species of lizard very much 

 larger than the house lizard. In all the females, many of which 

 were pregnant, a calcium deposit was present in the gland. In 



