112 MOLLUSCA. 
double, reflexed, continuous. The secondary lip being very robust, 
distant from the true lip, in profile looks like an obtuse spine or beak, 
at the base of the shell. 
Length nine-fortieths of an inch; diameter three-fortieths of an 
inch. 
Found at Rio Janeiro. Couthouy. 
In size and colour this species much resembles J. Cumingiana, 
Adams, which has been pronounced to be a variety of T. scalaris, 
Michaud; but that shell is smaller, has only eight bars, which are 
whitish, more elevated, and acute; and unless that species is subject 
to extraordinary variation, must be regarded as different. 
' Figure 128, front of the shell, enlarged; 1284, side of last whorl, 
enlarged ; 128 4, natural size. 
PLANORBIS VERMICULARIS ( Gould). 
Testa parva, fornicata: spira planulata, apice depresso; anfractibus 
quatuor, cylindracets, ultimo prope aperturam deflexo: subtus concava: 
apertura perobliqua, elliptica. 
Planorbis vermicularis, Goutp; Proceed. Boston Soc. Nat. Hist., 11. 
212. June 1847. Expedition Shells, 42. 
SHELL small, dome-shaped, minutely striated by growth, white, 
(probably bleached by the liquor from which it was taken ;) whorls 
four, breadth and height about equal, the last one deflected near the 
aperture, rounded at periphery, tip depressed, suture very deep, the 
whorls sloping towards it; base cup-shaped, exhibiting all the whorls. 
Aperture exhibiting a very oblique section of a cylinder ; lip embracing 
about one-half the height of the last whorl and joined by callus. 
Diameter one-fifth of an inch; height one-fifteenth of an inch. 
Found in the interior of Oregon. Drayton. 
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