54 
Chatham Island, one of the Gelepagos group. Five, viz. nux, cal- 
vus, eschariferus, unifasciatus , and rugidosus, are described forms ; 
two, to wdiich I have applied the names chemnitzioides and acha- 
tellinus , are new, and very curious. Of these latter, the first is 
singularly isolated in many of its features, though bearing a resem¬ 
blance sufficient to indicate an affinity with certain elongated and 
turreted Bulimi , natives of South America. The other is equally 
distinct from any known members of this genus; but, moreover, 
instead of linking, as the majority of the Gelepagos land-shells do, 
the fauna of those singular islands with the American continent, 
rather points, as it w^ere, in the opposite direction, and distantly 
indicates affinity with the fauna of the Sandwich Isles. 
Unfortunately less certain as to exact locality, though contained 
in a box labeled “ Panama,” is a curious small elongated Bulimus, 
to which I have given the name fimbrialus. A form such as this, 
suggests, when we bear in mind the varied characters of its congeners, 
considerable doubts as to the value of the generic sections at present 
generally received among the Pulmoniferous Mollusca. We speak 
of Bulimus, Helix, Pupa, Achatina, and Balea, as if they were so 
many marked groups, the species in each assimilating to ideal generic 
types, whereas the difference between certain forms of so-called Bulimi 
and others placed under the same generic name is greater than be¬ 
tween many Bulimi and Helices or Pitpce. Without assenting to 
the view T s of Ferussac, which would have amalgamated the genera 
into one, on account of the similarity in external characters of the 
soft parts of the animal, and fully admitting that in certain tribes 
the shell alone may become a most important source of generic cha¬ 
racter—in other words, granting that in certain groups the sources 
of generic distinction may lie in the pneumo-skeleton—I do think 
that we have not yet attained a natural arrangement of the Pulmo¬ 
niferous Mollusks, and until we have solved that problem, w r e shall 
be seriously impeded in the study of the laws of their distribution 
as well as of their organization. 
Besides the Bulimi already named, there are specimens of Bulimus 
iostomus, B. Harlwegii , and a beautiful new species lately described 
and figured by Mr. Pieeve under the name of Bulimus KelleUii, all 
probably from the Equador ; Bulimus alternatus, from Panama ; 
and Bulimus millecheilus, marked from the Sandwich Islands, though 
this curious and beautiful shell is not known to inhabit that locality ; 
nor have we evidence sufficient that the specimen brought home by 
Lieut. Wood was gathered there. Hitherto it is only known from 
“ San Christoval, south-eastern island of Solomon’s Group, north¬ 
east coast of New Holland” (Pieeve), from which locality the speci¬ 
mens in Mr. Cuming’s collection were obtained, and the single ex¬ 
ample now referred to may have possibly been brought away from 
the same place. 
Of the curious genus Achatinella, two species, livida and alba, are 
in the collection, both procured at the Sandwich Islands. 
Of Succinea there is a new species, marked from Mazatlan ; T 
have named it Succinea cingulata. 
