very full in the throat, and, on gentle pressure, I got out two young Water Voles.) The mechanism of the jaws is indeed peculiarly fitted for the passage of bulky articles of food, a feature common to the Ophidia group.
3rd. The cubic capacity of the œsophagus (gullet).
This is a crucial point. If the Adder does swallow her young it is to be presumed that there must be room in every average-sized Adder's gullet for an average-sized family.
The capacity of the gullet can be estimated by the simple process of dilating it to its full extent with air through a blowpipe. I did this in the presence of a naturalist last week; his comment was, "There is room for twenty young ones, but for forty I think not." The average length of the gullet is 9 in., and the average diameter, when distended, 1 in., the average circumference 3⅓ in. Young Adders can curl themselves up in a remarkable way, and I have no hesitation in saying that the capacity of the œsophagus is sufficient to hold the young. My conclusion is that, theoretically considered, there is no anatomical reason why the Adder-swallowing theory should not be true.
