GASTEROPODA. 141 
tudinally plaited, and all of them have fine, raised, revolving lines, 
most conspicuous near the suture, and about the base; the suture is 
deep, and in most cases there is a conspicuous slope of the whorls to- 
wards it, both above and below. The aperture is less than one-fourth 
the length of the shell, of an ovate form, rounded or very slightly pro- 
jecting in front. The lip is sharp, and the throat livid. 
Length seven-eighths of an inch; breadth one-fourth of an inch. 
Found at the island of Upolu, Samoa Group. Couthouy. 
It has the form and size of M. abjecta, Hald., from Alabama ; also, of 
M. truncatula, Lam. It is more robust, paler, and the folds are more 
prominent and on more whorls than in M. plicata, Lea. 
Figures 158, 158 a, 158 3, three views of the shell. 
MELANIA SILicuLa (Gould). 
Testa parva, gracilis, sub-cylindrica, truncata, epidermide Susco-castaneo 
induta: spira anfractibus ad quatuor superstitibus, rotundatis, sptra- 
liter liratis, supernis longitudinaliter plicatis ; ultimo Jusco-zonato ; 
sutura bené impressa : apertura rotundato-ovata, antice vir producta ; 
Sauce subviolacea. 
Melania silicula, Gouty ; Proceed. Boston Soc. Nat. Hist., ii. 224. 
June 1847. Expedition Shells, 46. 
A small, slender, nearly cylindrical species, covered with a some- 
what clouded, dark chestnut epidermis. There are about four 
entire whorls, several others being lost from the tip; they are well 
rounded, and marked with numerous, fine, revolving threads, and all 
but the two largest ones are longitudinally plaited. The aperture is 
small, rounded-ovate, scarcely produced in front, and about one-fourth 
the length of the shell. The throat has a pale violet tint. The last 
whorl has a dark, narrow band around it, just at the junction of the 
lip to it. 
Length half an inch; breadth one-fifth of an inch. 
36 
