78 



CURRENT LITERATURE. 



such names to be the outcome of an inability to grasp the broad facts of 

 Biology on the part of the describers, followed by the 

 J . blindness of individuals who specialize without possessing 



I I a general knowledge of the science in which they dabble. 



There is this to be said, however, that Mr. Taylor 

 (! might have been more prodigal of varietal names than he 



i r| has been, though the terminology that allows of the 



J \\ labelling of a large Helix a'ipcrsa " showing the effect of 



I, ;| a favourable environment," var. viajor, while a small 



it jl example of the same shell showing the reverse is termed, 



f'l ;| var. minor, must appear to most minds to be — well, one will 



■^ * say — rather eccentric. Whatever one's idea of varietal 



J I characteristics may be, surely one would not include such 

 differences from the general form as are temporary, only 

 affecting the individual and not its descendants, unless sub- 

 jected to the same environment. 

 Figure i6o. Figures 151 and 152 illustrate some of the remarks on 



(^^JleN^c^mwiuhta ^^^'^ aperture, while periostracal hairs are well shown by 

 Alder. '' Figure 160. 



Under the heading of colouring, much interesting matter has been 

 brought together. It is to this part that Plate II. refers, and although the 



J 



Figure 210. /A7/.r a.«/)('r.w. showing 

 " interiuiited " bands. 



Figure 194. Ilcli.r cuiniata, 

 variation probably avoided 

 by sheep. 



introduction of tropical shells may add to the brilliancy of the plate, yet the 

 advisability of figuring foreign species in a British monograph may be 

 questioned. An illustration of the distinctly marked variation of Helix virgata 



.d 



Figures 229, 230, 231. LiiiDiaca pinger, froni a pool near Geneva.. Showing the 

 deformation of the columella and base ot the shell, assumed to be caused by Jlydia virklii. 



supposed to be avoided by sheep, grazing on the downs, is reproduced above 

 Figure 210 is a handsome variation of Helix asbersa. 



