344 LITTORINIDZ. 
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 imtro- 
duction of phantoms into our records, instead of soundly 
settled species. I 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 
