150 BRITISH SERPENTS. 



eggs will be beautifully seen at this stage, and should 

 be noticed before cutting out the eggs by dividing the 

 oviduct on the distal side of each ligature. This done, 

 the two oviducts full of eggs can be lifted out bodily 

 on to a dish. When lifting out observe which is the 

 right and which the left oviduct, as the number of 

 eggs frequently differs on the two sides. If the 

 dissection has been carefully done and nothing torn, 

 the eggs on the dish will appear as shown in the 

 illustration opposite, which is one of the series of 

 dissections I made in investigating this question of 

 the number of young. 



Result of series of dissections. — During the 

 months of July and August in 1899 and 1900 I made 

 23 dissections of gravid female adders in the manner 

 just described. The average number of young in that 

 series works out at 13. I freely admit that a series 

 of 230 dissections, instead of 23, might give a slightly 

 different result, but should not anticipate any great 

 divergence from the average given. The fewest found 

 was in a specimen which contained 7, and the greatest 

 number was 20, also in only one specimen. One or 

 two contained 8 or 9, but the great majority were 10, 

 11, 12, 13, 14, or 15. I have found it the exception 

 for an adder to contain more than 15 young or less 

 than 10, and can hardly credit that as many as 40 

 could be carried to full time for reasons stated later. 

 My conclusion may be subject to modification after a 

 larger series of dissections ; but it is not a hasty esti- 



