314 The Philippine Journal of Science m» 



twenty of the male specimens studied a calcium deposit was 

 found in only four, while in the remaining number there was a 

 complete absence of the calcium. Here, again, is the striking 

 difference in the functional activity of the gland in the pregnant, 

 the nonpregnant, and the male lizards. 



Taylor, in an unpublished observation, has also seen a calcium 

 deposit in many of the young lizards after hatching. 



The calcium gland in Cosmybotus platyurus and Per opus muti- 

 latus are histologically identical. Under low-magnifying power 

 the gland is distinctly lobulated, with a pattern much like the 

 external surface of a mammalian lung. There is no distinct 

 capsule, and the external wall is surrounded by a loose con- 

 nective tissue reticulum. From the external wall trabecule ex- 

 tend into the gland, dividing it into follicles. Each follicle is 

 lined with a single layer of large cuboidal epithelial cells that 

 lie on a basement membrane. The connective tissue intervening 

 between follicles is extremely loose in texture. Between the 

 adjacent walls of the follicles is a rich capillary network. In 

 the active gland the follicle is filled with an amorphous substance 

 into which the cells have wandered. The cells that lie near 

 the epithelial wall retain their cellular characteristics distinctly. 

 As they wander farther out into the center of the follicle, they 

 become more and more disintegrated. Whether or not these cells 

 take an active part in the production of the amorphous calcium is 

 not definitely known, although it seems probable that they do 

 play some role in the formation of calcium by the gland. The 

 peripheral follicles are, as a rule, smaller than those placed more 

 centrally. Voluntary, or striped, muscles often extend with the 

 trabecule into the medullary portion of the gland. 



In Hemidactylus frenatus and H. luzonensis the gland is com- 

 posed of a reticular structure forming numerous small follicles, 

 which have never been found to contain a deposit of calcium. 

 However, in the pregnant lizards a calcium milk is found filling 

 the sinuses on the superior and medial sides of the orbital cavity 

 as well as the sinus in the region of the occipitoparietal suture. 



SUMMARY AND CONCLUSIONS 



The calcium gland in the region of the neck of the common 

 house lizard is undoubtedly an auxiliary to the auditory organ, 

 inasmuch as it supplies a calcium salt for the formation of 

 the otoliths of the ear. 



In pregnant lizards the calcium gland is thrown into a greater 

 functional activity, which immediately decreases when the cal- 

 cium shell about the egg substance is formed. 



