40 TERRESTRIAL MOLLUSCA INHABITING SOCIETY ISLANDS. 
carinato-costata, subtus subobsolete costata; anfr. 6, carinato-rotundati, seriebus 
radiantibus pilorum brevium muniti, suturis bene impressis. Apertura subrhomboidea, 
lamella unica in anfr. penultimo munita. ‘Testa saturati castaneo et fulvo fusco tes- 
sellata. Diam. 5, axis 2 mill.” (Pease). 
I collected Mr. Pease’s type specimens at Huaheine : and, though he was well aware 
of the fact, yet he gave the wrong habitat “Tahiti” to this and several other new 
species obtained on the former island. 
The base is never “ carinato-costata.” It is rounded or faintly angulate. His 
* pilorum-brevium ” exists in immature examples only. 
Eight years after receiving from me a lot of Raiatea specimens of this species he 
published his “ Pithys ? celsa” (1. c.). His description is as follows :— 
Testa discoidea, late umbilicata, radiatim tenuiter, regulariter rugoso striata, 
concentrici irregulariter sulcata aut tenuiter costata; spira depresso elevata, convexa ; 
anfr. 7, rotundato-convexi, plerumque angulati, ultimus ad peripheriam rotundatus ; 
umbilicus 7; diametri occupans; apertura vix obliqua subcircularis, lamella unica 
volvente instructa ; perist. simplex rectum ; radiatim fusco et albido tessellata. Diam. 
6, alt. 3 mill.” (Pease). 
The following year he redescribes it under the name of “ Endodonta celsa” (1. ¢.), 
without referrmg to his former diagnosis. I repeat his description :— 
“'T. orbicularis, solidiuscula, late umbilicata, tenuissime radiatim creberrime 
striatula, rufo et albido pallide tessellata; spira elevata, apice obtusiusculo, nucleus 
rufescenti-fuscus, sutura bene impressa ; anfr. 7, convexi, interdum concentrice elevato- 
striati, rarissime sulcati aut angulati, ultimus ad peripheriam obtuse angulatus, subtus 
rotundatus ; apertura obliqua, fere circularis, lamella unica in anfr. penultimo munita. 
Diam 7, alt. 35 mill.” (Pease). 
He gives the correct habitat ‘* Raiatea.” It will be observed that there is some 
discrepancy between the two descriptions of celsa, proving it to be a variable species. 
His measurement, 6 mill, is correct, but his last one, 7 mill., is larger than any 
specimen known to me. 
Having a second time gone over the same ground and collected hundreds of speci- 
mens, both on Raiatea and Huaheine, I do not hesitate, after a careful study of the 
numerous examples, to add both acetabulum and celsa to the synonymy of obolus. 
I am not positive, but I think I am correct in referring Mousson’s intermixta (which 
I collected at Raiatea) to Gould’s species. My Barffi, MS., is the Huaheine shell. 
This species, in the shape, and the absence of palatal lamin, is nearly intermediate 
between Endodonta and those species of Patula with the single parietal lamina. 
The height of the spire varies from a perfect plane to a depressed cone, hence a 
deeper or shallower umbilicus. They also vary in the distinctness of the periphery- 
keel, and some have that part of the shell obtusely angular, without the slightest 
