KKWAN RIVKK. 
52 F 
Platijco.raa rnmpnc.him, sp. nov. 
Slioll Liirljinato, impel forato, a little wider tliau hi^h, spire small 
aufl sliort.. Whorls ecj-tainh' three ami pruha' ly fus many as four or 
five in perfeei, spocnmena (the apex hein^ broken in botli of those 
collecteil) roumh'd, closely coiled and inereiusing rapidly in size; outer 
whoil inllated and expandtul, willi tM'o faint low rounded spiral plica- 
tions near and at the aperture in young specimens, and from three to 
four in adult ones. 
Surface marked with numerous, close srt, transver.se lines of growth, 
that are ilexuous where t hey cross the spiral plications. 
I'ikwan river, portage road at falls : one ap)»arently adult and one 
half grown specimen. The former, which is well preserved and neaily 
perfect, is thirty tive millimetres wide, and was probably about thirty 
mm. high when perfect, allowing two mm. for a small piece broken 
off at the apex. 
Diaphnrnutoma pt’rforntinn, sp. nov. 
.Shell depressed t urbinate, much wider than high ; syiire short, raisi'd 
veiy litthi above the highest, level of the outer whorl ; base narrowly 
but flecjily umbilicated. Whorl, s five, increasing rapidly in size, those 
of t he sjiire (latlened above and rounded below ; the outer one rounded 
and ventricose, but dcpre.ssed at the suture above ; umbilical margin 
roundetl and very indistinctly delined. Aperture rounded subovate, 
pointed above and slightly insinuated on the columellar side by the 
encroachment of the preceding whorl, wider and rounded below; lip 
thin atid .simjile ; characters of the columella not well shown in the 
only specimen collected. 
Surface marke.d with numerous clo.se set, nearly straight and very 
minute, transverse raised lines, that are scarcely vi.sible without the 
aid of a lens : also by a few larger and more distant imprc.s.sed lines 
of growth. 
Kkwan river, middle rapid : (>nc nearly perfect specimen, with the 
test preserved. 
'I’his shell seems to be referable to the genus Plalyosloma, Conrad 
(1S42), but Lindsti’um asserl.s that this name is preoccujiied b}-^ Klein 
in 175.1, by .Meigen in 1S0.1, and liy L. Agassiz in 1829. Kor this 
reason Dr. Paul Kischer (in 188.5) propo.sed to distinguish Conrad’s 
genus by the name Dlophorostoyna, though r.indstrbm maintains that 
both Plahjoiitoma^ Conrad, and Strophosfi/lns, Hall, are mere synonyms 
of Platyceras. Fischer explicitly states that the only difierence between 
