INTEGUMENTAL GLANDS OF CROCODILIA 587 



which are possessed by both sexes, is obvioiisl}^ hedonic. The sexes are 

 probably able to follow and find each other, thanks to the streak of 

 scented water left behind each individual. 



CLOACAL MUSK GLANDS 



As in the skunk andother animals, the alligator possesses a pair of 

 well-developed glands, one on each side of the cloaca, into which 

 they open. These glands, like the dorsal glands, are developed 

 from the lower layer of the epidermis, and are first seen in embryos 

 of slightly more than 7 cm. total length (fig. 12). In these 

 embryos the penis (fig. 12, pe) is a large, thick organ projecting 

 markedly from the cloaca to the exterior. As seen in figures 12 

 and 13, the glands are thickenings and slight invaginations, eg, of 

 the epidermis in the lateral walls of the cloaca, cl, rather nearer 

 the surface than the bottom of the cloaca; they are at some distance 

 posterior to the opening of the rectum into cloaca. The epi- 

 dermis, e-p, is somew^hat thicker in the cloaca than over the 

 general body surface, consisting in the former region of two or 

 three layers of cells instead of the single layer, beneath the 

 periderm, seen over the body. The gland now consists of the 

 above mentioned thickening of the lower layer of epidermis 

 (fig. 13, eg) which is slightly invaginated and consists of about 

 six or eight layers of cells, somew^hat more loosely arranged near 

 the surface than around the periphery or deeper part of the 

 thickening. The periderm, p, in some sections seemed interrupted 

 at the point of invagination, but it is seen to extend to the very 

 bottom of the duct in later stages, this interruption was probably 

 an artifact or an optical illusion. 



Opposite this point of origin of the gland the penis, pe, showed 

 a slight thickening or bulge of its wall. 



Figure 14 show^s the cloacal region at a slightly later stage of 

 development. The gland, eg, is somewhat more elongated in 

 shape and exhibits a lumen of considerable depth, slightly bi- 

 furcated at its bottom. The relation of parts wdll be understood 

 by comparing this figure with figure 12. This embryo was about 

 9 cm. long, from tip of snout to end of tail, measured along the 

 greater curvature of the body. The next stage is an embryo of 



