PROCEEDINGS: FEB. II, I9II. 2I9 



D. — Ornament of the Unionidiv : — This is seen liest in foreign forms, and can he 

 classified into the following types : i., Confined to the umbonal region, e.g., 

 U. titmidtis. ii., Occupying the whole valve in a more or less degenerate 

 form, e.g., Qiiadrula lacryniosa (Lea), iii.. Occupying the whole valve and 

 fairly regular, Parreysia nyassaeusis (Lea), iv. , Occurring after an unor- 

 namented area as irregular pustulations, Qiiadrula piistiilata (Lea). 

 Relationships of the Uniouida :— The older theory connecting them with the 

 7rigoniid(2 is supported by their teeth and ornament. 

 Mr. J. Wilfrid Jackson gave a few short remarks on the Pearl-mussel, J\/ar- 

 garitana vtaroaritifera (L. ), a very large collection of which was exhibited, the 

 main contributors being the Manchester Museum ; Dublin Museum ; Department 

 of Agriculture of Ireland, Fisheries Branch (these two last collections lent to Mr. 

 Jackson for the purpose of study) ; Messrs. R. Welch, R. Standen, J. Wilfrid Jack- 

 son, and the Rev. G. A. Frank Knight. 



400th Meeting-, held at Manchester Museum, March 8th, 191 1. 



Mr. E. Collier in the chair. 



Additions to the Library announced and thanks voted : 



" New Species of Shells collected by Mr. John Macoun at Barkley Sound, 

 Vancouver Island, British Columbia," by W. II. Dall and Paul Bartsch. "Descrip- 

 tions of New Mollusksof the Family Villi nelliace. from the West Coast of America," 

 and " The Recent and Fossil Molhisks of the Genus Alabina from the West Coast 

 of America," by P. Bartsch {from the respective authors) ; and the usual periodicals 

 received in exchange. 



New Member Elected. 



Miss M. C. March, Healey Giove, Burnley, Lanes. 



Resignations. c 



Mrs. L. A. Baker. Professor W. A. Ilerdman. 

 Papers Read. 



" Note on an early Spinous Stage in Corbida gibl/a," by Anne L. Massy. 



" Conchological Notes from La Plata, Durban, and Bombay," by Lionel E. 

 Adams, B. A. 



" Descriptions of new Colour ^'arieties ot Donax variegaius Gmelin from the 

 Channel Islands," l:iy R. Woodcock. 



Exhibits. 



By Mr. R. Woodcock : Specimens of Donax variegatus, type and varieties, to 

 illustrate his paper. 



By Mr. G. C. Spence : Plaiiispira liedtkii and P. ohiensis from Obi Island ; 

 specimens of Cerion from Nassau, Bahamas, including an exam]ile of Ceriofi glans 

 with double lip. 



By Mr. C. II. Moore : Fine examples of Melapiiini lineatuni var. bulbiforniis 

 from New Zealand. 



By Mr. J. Wilfrid Jackson : Shells of Uiiio linnidiis from river gravel on the 

 banks of the Avon near Bath. 



In the Special Exhibit of the Genus AmpJiidroiiiiis, a large number of species 

 and varieties of the brilliantly coloured shells of this interesting group was shown 

 by Messrs. J. Kidson Taylor, Edward Collier, J. R. Hardy, R. Standen, G. C. 

 Spence, and Mrs. Gill ; also the fine series in the Manchester Museum collection. 

 Mr. Collier made some remarks upon the distribution of the genus, and pointed out 

 the chief characteristics of the more remarkable forms. 



