264 WEST COAST SHELLS 



tions and were never known to really get out of 

 breath. But in spite of their deliberation they accom- 

 plish quite extensive results, if you give them time 

 enough. It is a favorite joke of the citizens of some 

 brisk town to declare that the inhabitants ot a rival 

 city do not eat snails because they cannot catch the 

 pesky creatures, presumably because the snails are 

 more fleet of foot than the aforesaid neighbors. They 

 are eaten, however, in some parts of the world, and 

 are esteemed a great delicacy. Most of the snails 

 breathe by means of a simple lung, or air-sack, which 

 opens on the right side of the body, as is plainly 

 shown in the picture of the yellow slug, Figure 264. 



Figure 261 represents the Northern 



Selen, Selenitcs vancouverensis^ Lea. 



It represents, however, a sinistral 

 Fig. 261 form of the shell; but when viewed 



in a looking-glass it appears in the more natural 

 form. This remark will apply to other figures in so 

 far as one might wish to see how a reverse shell 

 would look. Nearly all ot our univalve shells are 

 dextral, or right-handed; a few, like the Physas, are 

 always left-handed, or sinistral. A good many 

 tropical shells show more diversity in their method 

 of coiling, anci some specimens of the same species 

 will turn to the right, while others will "per- 

 versely" roll the other way. In Figure 102 we have 

 a good example of a sinistral shell. 



Some specimens of this Selen grow to a consider- 

 ably larger size than the hgure. The epidermis is 

 yellowish green, while the interior of the shell is 

 white. There are five whorls, the last one being flat- 



