344 LITTORINID^. 



as the typical L. rudis and its variety L. tenebrosa inhabit 

 the highest levels of the sheltered and protected estuaries. 

 They are the parents of all the dwarf varieties, the L. patula, 

 L. subsaxatilis, L. neglecta and L. fabalis, &c. 



As a proof that habitat is the cause of these dwarf varieties 

 of the L. rudis, I mention that the L. littorea, in company 

 with them, at a few yards' lower level, are small, stunted, 

 and nearly as dwarfish. By the favour of Mr. Bean of 

 Scarborough, I have compared his L. zonaria, L. rudissima, 

 L. neglecta, and L. fabalis with Devon specimens, and found 

 them identical; consequently I presume the animals are so 

 likewise. 



These so-called species are viviparous. How happens this 

 singular coincidence ? how is it that none of them follow the 

 plan of the reproduction of the other species ? This is a very 

 significant fact, and is, I think, a strong circumstance, in con- 

 junction with the positive similarity of the animals, in favour 

 of my position, that the spurious species belong to L. rudis, 

 and of course follow the habitudes implanted by nature in the 

 parent. It may be asked, does not the very important fact of 

 the viviparous reproduction of L. rudis and its varieties indi- 

 cate something more than specific distinction ? I partook of 

 this opinion, but on consulting a naturalist of the highest 

 authority, he informed me, that in the lower classes, the fact 

 of an animal being viviparous, without other circumstances, 

 when its congener was ovo-viviparous, did not constitute suffi- 

 cient grounds for generic distinction. The question is open, 

 and I leave the solution of this problem to those who are 

 better versed than myself in the mysterious laws of nature 

 which relate to the genesis of the Mollusca. 



I could adduce many more examples, of various values, of 

 the sad confusion that has crept into and disfigured this highly 

 interesting department of natural history, from the intro- 

 duction of phantoms into our records, instead of soundly 

 settled species. T refrain, and rest for the present on the 

 great examples I have adduced in illustration of these obser- 

 vations, on the principle that " omne majus in se minus con- 

 tinet." If the preceding remarks have the effect of causing 



