394 HETEROPHROSYNID #®. 
discrepancies. Philippi unaccountably omits all mention of 
the principal peculiarity, the curious operculum, but he does 
say that the animal departs somewhat from those Rissoe 
he has examined, both as regards the organs and the shell ; 
and I add, that with the exception of the very short muzzle 
and depressed line in the after-part of the foot, there is not 
another external organ that has much concordance with the 
typical Rissoe. 
Neither can it be associated with Jeffreysia, which mdeed 
agrees with it, essentially, in respect to the operculum; but 
the animals of the two are very different. I have therefore 
proposed for it a new genus, which ought, I think, with Jef- 
freysia, to form a family intermediate to the Littorinide and 
Pyramidellide. 1 have omitted to mention that M. D’Or- 
bigny’s subgenus Rissoina cannot receive it, as with a testa- 
ceous operculum and apophysis, it is of the spiral or Littorini- 
dan type, whilst the present object is of subannular elements ; 
and I consider the operculum, though so much neglected, to 
afford a most important generic and differential diagnosis ; 
but mdependent of these points, I could not, agreeably to my 
views, accord with such an allocation. I repudiate all sub- 
genera, which I consider as an awkward attempt to define what 
is undefinable—an intermediate condition between a genus and 
a species. I think, when a species: is so discordant with the 
generic type, that it ought to merge elsewhere, and take on a 
substantive capacity and become the type of a new genus. 
There can be no objection to the term sub when used ad- 
jectively to qualify a word, as subannular, subrotund, and 
subsymmetrical, &c., but not substantively, as then it be- 
comes the source of innumerable absurdities: with me a 
genus has no intermediate state beyond species and their 
varieties. 
I would therefore submit to malacologists, as I have 
shown that no existing genus can with propriety receive this 
curious creature, that a new one be constituted for it, and en- 
titled Barleeia, as a just recollection of the exertions of a gen- 
tleman who loses no opportunity of enriching science with 
living objects from the Great Book of Nature; and though 
