OCCASIONAL NOTES. 351 



of the grass-snake take from fifty to ninety days, according to the 

 temperature. It is curious that serpents which are obviously 

 very nearly allied in their anatomical and physiological charac- 

 teristics should often differ in this respect — the boa and python, 

 for instance ; while among colubrine snakes we often find the 

 difference marked between different species belonging to the same 

 genus. Tropidonotus natrix lays eggs; T. leberis and T.fasciatus 

 produce their young alive. 



I have not seen the retention of derived heat noticed in any 

 previous records of this subject, but I should be glad to know if 

 mine is an exceptional or accidental case. A Ringed Snake is 

 said to have hatched her eggs in the Jardin des Plantes, in Paris, 

 on three successive occasions ; I am not aware whether any 

 elevation of the bodily temperature was discovered or not ; but 

 with artificially heated surroundings, minute differences would be 

 difficult to obtain confidently. Possibly, too, the storing of heat 

 from the floor among the eggs may have influenced some of the 

 results which have been gathered from incubating pythons and 

 other large serpents ; and it may be that in some cases the 

 incubation is confined to a mere defensive shielding of the eggs, 

 unattended by any further phenomena. I believe that this is the 

 first instance in which thermometrical observations have been 

 made under ordinary atmospheric conditions. 



OCCASIONAL NOTES. 



Variety of the Mole. — Early iu Juue last I examined a somewhat 

 similar variety of the Mole to that mentioned at p. 263. It bad been 

 trapped a few days previously near Souldern, in this county. At first sight 

 the colour of the specimen appeared to be a dusky cream, but, on raising 

 the fur, I found that it was of a bright, though pale, apricot colour, each 

 hair having a dusky tip. The colours were warmer and deeper on the lower 

 than on the upper parts. — Oliver V. Aplin (Banbury, Oxon). 



Bottle-nosed Dolphin in the Colne. — On July- 25th, after con- 

 siderable chasing, a specimen of this Dolphin, Delphinus tursio, was shot in 

 the Colne, near Rowhedge. It was a female, nine feet long ; the teeth were 

 sharp, and not at all truncated. It was, therefore, probably not a very acred 



