Variations in the Animal Kingdom. 13 



constant in form when in enormous masses ^^ J* ^^^^^^^^^^^ 

 in. When, however, it occurs in very small """J/J^' ^^ ^7^^^^ 

 ones and twos, as it does on some parts of our ««a«\t^^ f ^J^' 

 always abnormal, being most ^^^^V^^^ \^f^f '^^re are 



a}u=^s:i=^i:J;=Se3^ 



-SSln^tSo^nSK^e ^n=: ^^^ 

 few that\ave survived have done so because there has been a 

 gi-adual attempt through many g^^^^'t^^^^^^^.f^^^l^Xn in 

 Lw surroundings, whatever they may be, ^^f^*^^^^^^^"Xt the 

 structure and paucity of survivors seems to show that ^ne 

 strutle to adiust the correspondence is a severe one and that 

 so fS as those particular localities are concerned, the spec e 

 'and the variation's are doomed to -tinction on the goun^^^^^^^^^ 

 a form that exists only in ones and twos, and under adverse 



" Theirs oTotL'rTn^ttnce that I would wish to quote before 

 leavLTthe Mollusca. and it is the question of abnormaWo^^^^^^^ 

 oiBufcinum and Ftcsus from estuarme localities, and the smistial 

 forms of both these and other genera. 



Thave a remarkable series of Bwcmmm from the aiea ot tne 

 Thames aUSedway estuaries. Many of these are smist^^l 

 whilst many of the others are exceedmgly curious m fi^. so"^^ 

 beins elongated, others approaching the shape of a Marex 

 There is httle doubt that an estuarme area is not conducive to 

 the norma growth of this genus, and the endeavours to adjus 



r„SrriItIs^fal;tnTof'thisVoies from the North 

 ^iBTega^dsTtoS forms, it is very diiBcull, if not ^possible 



cau^e eSsted to account for this strange reversion of condition 



^^^Z::^:':^i^^ of form are not - noticeab^ for 

 the simple reasou that we see so comparatively few of even the 



