IN your article on “The New Museum of Natural History” (NATURE, vol. xxiii. p. 549 et seq.) it is stated that the specimen of Archæopteryx macrura in the British Museum is headless. Will you permit me to draw attention to a nodule projecting from the slab in which the fossil lies, which bears a striking resemblance to the cerebral portion of a bird's skull? It is some years since I visited the museum, but I recollect feeling satisfied at the time that the nodule was the missing head, and worth while disinterring from its surrounding slate.