To Frank Hurndall   20 September 1881

Dear Sir

Many statements have been published of frogs and toads having been found in completely closed holes in rock, timber, coal, &c. but they are quite incredible.¹ No animal can live without oxygen and food. D^r. Buckland many years ago tried experiments, but all his buried specimens died.² The most probable explanation which has been suggested is that the animal crawls into holes whilst very small and cannot escape, but feeds on any insects which may crawl in. As for the mouth of the frog being closed in the case referred to by you, no naturalist would credit it for a moment, unless the animal had been carefully dissected by an experienced anatomist.

Dear Sir | Yours faithfully | Chas. Darwin