1909.] ON THE RECENT BIOLOGY OF SOME LIVING SHELLS. 745 



which is one of the items mentioned in the catalogue of the sale of 

 the collection, of which a copy is preserved in the British Museum 

 (Nat. Hist.). William Bullock originally had a museum in 

 Liverpool, but moved his collection to London about 1809, and 

 apparently built the Egyptian Hall for its reception. The 

 collection was sold by auction in London in the spring of 1819, 

 when a number of specimens were purchased for the British 

 Museum by Dr. Leach. Large extracts from the sale-catalogue 

 are given in the second volume of the ' History of the Collections 

 of the British Museum (Nat. Hist.).' The source of the plate, 

 which was not known to the exhibitor, is indicated in the legend 

 to the illustration. 



The following papers were read : — 



1. Some Living Shells, their recent Biology and the Light 

 they throw on the Latest Physical Changes in the 

 Earth. — I. Mija arenaria. By Sir Henry H. Howorth, 

 K.C.LE., D.C.L., F.R.S., F.Z.S. 



[Received June 5, 1909.] 



(Text-figures 236-243.) 



In his papei- on the proofs of a genei-al rising of the land in 

 certain parts of Sweden, published in the '■ Philosophical Trans- 

 actions ' for 1835, p. 10, Lyell, in speaking of the living testacea 

 of the Baltic, says : — " In regard to the shells I may observe that 

 the Mya are7taria is the only one found by me in great abundance 

 in any part of the Baltic which I did not see among the fossils of 

 any of the localities already mentioned or those afterwards to be 

 alluded to further to the North," i. e., in the raised beds. This 

 notable observation, then made for the fii'st time, lay dormant 

 for many years, and it was not until 1872, when engaged in ex- 

 ploring the coast of Skiine, the soutliern province of Sweden, that 

 Nathoi'st remarked of an old raised beach situated 8 or 10 feet 

 above the sea-level at Alnarp, near Malmo, in which the littoral 

 shells, then living in the adjoining Sound, were found, that Mya 

 arenaria, which is now common there as a. living shell, did not 

 occur, aiid he went on to suggest that it may have been a recent 

 immigrant into the Baltic. 



Nathorst's suggestion was presently confirmed in a remarkable 

 manner by C. G. J. Petersen on Danish ground. In Rordam's 

 memoir on the raised beaches of Zealand he in 1892 called 

 attention to the fact that Alya arenaria, although such a tooth- 

 some mollusc, had never been found in the kitchen -middens of 

 Denmark, nor in the raised beaches of the Isefiord, &c., which 

 synchronize with them, and he concluded very reasonably that 



