214 



ZOOLOGICAL SOCIETY BULLETIN 



CHAMBERED NAUTILUS. 

 From a radiograph by Dr. H. G. Piffard. 



t'very chambered cell. 



M'here its Jim dreaming life was wont to dwell. 

 As the frail tenatit shaped his growing shell. 

 Before thee lies revealed, — 

 Its irised ceiling rent, its sunless crfpt unsealed^ 



— The Chambered Nautilus. Oliver Wendell Holmes. 



SOME SEA-SHELL RADIOGRAPHS. 



'T'HE Zoological Society is indebted to Dr. H. G. 

 * Piffard, of New York, for the use of a couple 

 of pictures of sea-shells from the excellent series of 

 radiographs made by himself. The X-ray is in 

 practical use by the medical, and some other pro- 

 fessions, but has not been specially utilized by 

 naturalists. Director Bumpus, of the American 

 Museum of Natural History, secured excellent 

 results with the X-ray in showing the vertebrx of 

 batrachians. Radiographs of sea-shells and other 

 objects of natural history are valuable in showing 

 structure as well as exterior outline and general 



appearance. It is quite possible that radiographs 

 would indicate differences between closely related 

 species that could not be shown in other ways. As 

 the nautilus grows it periodically secretes septa in 

 the back of the body chamber, wliich, gradually 

 increasing in size, form a series of air cells. These 

 are connected with a tube, and, when filled with air, 

 serve to maintain the relative weight of the growing 

 animal and its shell with the water. In museums 

 it is a common practice to split sea-shells with a 

 saw, in order to reveal features of structure. The 

 accompanying photograph of the nautilus, by Mr. 



