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xoitli a revision of thè Limnmidm of Authors. 
The authors state that this difFers from thè last species, in 
being thinner and smaller, in thè spire being more elevated and 
thè aperture being less produced in front. It has not b en 
fìgured, and no specimens bave as yet reached this country. 
Pompholyx, var. solida, Dall. 
The specimens received from Clear Labe through Mr. Har- 
ford differ essentially from authentic specimens of P. effusa. 
The shells, when compared with tiie last mentioned species, 
ditfer in thè following particulars : 
The most noticeable difference is in thè spire. In P. effusa 
it is nearly fiat, so that thè shell may be laid down upon thè 
apex without falling to one side. In thè species under con- 
sideration, thè spire is elevated, thè whorls are rounded below 
and slightly appressed against thè suture, while in P. effusa 
they are not appressed. The apex of my specimens is more 
prominent than that of P. effusa, thè shells are much more solid 
and strong. The last whorl of P. effusa is much larger, pro- 
portionally, than that of this species. In P. effusa tlie colu- 
mella is prominent and thè whorl falls away from it. In this 
species there is a prominent rounded ridge outside of thè colu- 
mella, and thè lattei’ is, so to speak, inside of thè aperture of thè 
shell, which is smaller proportionally, much less produced above, 
and less patulous than in P. effusa. A compai’ison of thè dentition 
shows that thè outer laterals of P. effusa are more denticulated, 
having from three to five dentations, while in this species there 
are normally only three denticles in thè outer laterals. The 
inner portions of both ribbons are, of course, similar, I bave 
examined a radula taken b}' Mr. Binney from an authentic 
specimen of effusa, and can testify to this. 
The specimens in question are elearly not P. eff'usa, yet in 
thè absence of typical specimens of P.leana stili rem ain s 
doubtful whether they belong to thè lattei’ species. Messrs. 
Adams’ description answers pretty well, except that my speci- 
mens, instead of being thinner, are much more solid than thè 
