NOTES. 73 



The species of the Subamalia section of Pollonera are well 

 worthy of a much more careful anatomical study than they have yet 

 received. Such forms as A. cretica and A. robici, Simr., will probably 

 throw much light upon the structure and affinities of the genus 

 which is at present very desirable. 



Out of seventy adult examples of A. sowerbii which I dissected the 

 amount of variation was exceedingly small, and by no means so well 

 marked as the differences found in young specimens. In A. gagates 

 even slight variations were not at all common, although one or two 

 occurred in the form and number of the accessory glands and the 

 constrictions in the sperm-duct, neither points of great importance. 

 The constancy in this genus of the generative organs certainly makes 

 these a very safe character for basing specific distinctions on, and as 

 soon as the minor differences are figured and described — if they 

 exist — -in the many doubtful forms, the sooner will the limits, &c, of 

 the trenus be better understood. 



NOTES. 



Mollusca as Purifiers of Water. 



A use, novel to me, of pond snails by the Chinese silk growers is described in 

 an official work which caught my eye by chance. This waif of malacological 

 information is so certain to escape recorders that I transcribe the passage for the 

 Journal of Malacology. 



Report on Silk. Imperial Maritime Customs of China, ii., Special Series, 

 No. 3 ; Shanghai, 18S1, p. 57. 



: ' The water used for reeling silk is taken from mountain streams, as being 

 the cleanest ; the water from wells is never used ; and if mountain water cannot 

 be had, river water is taken, which is cleaned by putting a pint of live shellfish to 

 one jar of water. There is a special kind of shellfish, called the pure water shell- 

 fish [here follows the vernacular name in Chinese characters] (fig. xxiv. ), found 

 everywhere in ponds, wells, and creeks. They first of all sink to the bottom of the 

 jar, and then by degrees make their way up its sides, consuming gradually all 

 impurities in the water within half a day or so. After the clean water has been 

 drawn from the jar, the shellfish are cleansed and put to the same duty again." 



As the three coloured figures are drawn in Chinese perspective the species 

 cannot be certainly identified. They are, however, sufficiently like Reeve's figure 

 (Conch. Icon., vol. xiv. , Paludina, pi. iv., f. 18) of Vivipara chinensis, Gray, to 

 assume that this the artist endeavoured to portray. — CHARLES Hedley, F.L.S., 

 Australian Museum, Sydney. 



Note on the Value of Laimodonta. 



I regret to suggest the alteration of a generic name, but I think for the reasons 

 appearing below that Laimodonta can hardly stand, and therefore propose : 



Enterodonta, num. nov. 

 1855 (Jan.). Laimodonta, II. and A. Adams, F.Z.S., 1854, p. 34. 

 Non. 1 841. Lai modon, G. R. Gray, Genera of Birds, ed. 2, p. 49. 

 Non. 1846. Licmodonta, Philippi, Zeischr. fur Mai., p. 98. 

 Non. 1847. Laimodonta, Bronn, Preisver. Ausl. Konch. Mus. Heidelberg. 



iv., p. 4. 

 Non. ? Laimodonta, Nuttall. MS. 



