-Jan., 1902 .] 
Variations in the Water-Snake. 
185 
from the neck. The pre-anal scale was found to be bifid in sev- 
eral of the snakes. Since the gastrosteges represent modified 
scales — scales such as occur on the dorsal and lateral surfaces of 
the body — these bifid scales may represent a primitive condition, 
where the ventral scales were similar to the dorsal scales. This 
bifidity of gastrosteges is not at all common in the adults of this 
species. Hence it seems probable that during succeeding moults, 
the normal gastrostege is finally obtained. A fact that points to 
this conclusion, indirectly however, is that on examining the 
labials, the fourth lower labial in specimen number 4 was found 
normal, but the epidermis, which had been loosened by the form- 
alin, was seen to have a bifid labial corresponding to, and lying 
immediately above, the fourth labial. This shows that in this 
case at least the labial was changed from a bifid to a single plate. 
The point of exit of the umbilical cord (i. e., the yolk-sac and 
the allantois), the so-called dermal umbilicus, being an old 
structure, would be definite in position to a certain degree. The 
number of gastrosteges anterior to this was found to vary to the 
amount of ten scales in different individuals. 
In respect to the scutse of the head, it may be said that little 
variation was found. The shape of the rostral, vertical, nasals, 
etc., presented little perceptible differences in the several indi- 
viduals. However, the number of post-oculars was found to be 
different in different snakes and on opposite sides of the same 
snake. In column 6 of the table these variations are shown. 
The first number represents the scales on the leftside, the second 
number those on the right side of the snake. Where the figures 
are the same, as e. g., 3-3, there is no variation in the number of 
postoculars on the two sides of the head. 
The number of longitudinal rows of scales was found to vary 
in each specimen and in different parts of the same specimen. 
Thus, in tracing a row of scales from head to tail, the row would 
often end in a V-shaped plan, formed by the approximation of the 
rows lying on either side of the row in question. The same was 
true of the mother. Therefore no attempt was made to tabulate 
them. 
The plate on page 184 shows the 33 young from a dorsal view. 
They should be counted from right to left to correspond with the 
table. It will be seen that the color pattern varies in the 
different snakes. All gradations, from regularly arranged saddle- 
shaped markings to chain-like figures are found. The greatest 
irregularity in the markings occurs in the region over the heart. 
The post-occipital collar is entire in some, as in specimen No. 1 ; 
in others, such as No. 12, this collar is cut into lateral moieties, 
all gradations existing between the two. 
If Cope’s conclusions are correct that, in reptiles at least, color 
variations arise posteriori}- and advance anteriorly, the regular 
