terrestrial mollusca inhabiting society islands. 
85 
There are twelve species recorded from this group, some of which arc undoubtedly 
synonyms, and one or two are doubtful inhabitants. The specific characters of tire 
various species are so feebly expressed that their correct determination, by the aid of 
the brief Latin diagnoses alone, is an almost hopeless task. 
S. HUMKROSA, Gould. 
Succinea humerosa, Gould, Proc. Dost. Soc. Nat. Hist., 1846, p. 183 ; Expl. Ex. Shells, p. 18, 
fig. 19. PfeiflFer, Mon. Hel., ii, p. 520. H. and A. Adams, Gen. Moll., ii, p. 128. Pease, 
Proe. Zool. Soc., 1864, p. 671 ; 1871, p. 472. 
Succinea Tahitensis, Pease (not of Pfeitfer), Proc. Zool. Soc., 1864, p. 677 ; 1871, p. 472. 
Rather common and rvidely diffused over Tahiti, where it lives on the ground in 
forests, and appears to be confined to that island. 
It may be distinguished from any other Society Islands species by its broad ovate 
form, very short mammillated spire, large depressed body-whorl, which usually exhibits 
a roundly angular shoulder, which suggested the specific name. Dr. Gould gives three 
whorls, though I can detect two and a half only in my numerous specimens. The 
color is rufus, pale corneous, yellowish amber and whitish. The revolving sulcations 
mentioned by the above author are not a constant character, and are common to other 
Society Islands species. 
S. Tahitensis, Pfeiffer. Plate II, fig. 2. 
Succinea Tahitensis, Pfeiffer, Proc. Zool. Soc., 1846, p. 109; Mon. Hel., ii, p. 522. H. and 
A. Adams, Gen. Moll., ii, p. 129. 
Succinea ovata, “ Pease,” MS. Carpenter, Proc. Zool. Soc., 1864, p. 675. 
Succinea papillata, Carpenter (not of Pfeiffer), Proc. Zool. Soc., 1864, p. 675. Pease, 
Amer. Jour. Conch., 1867, p. 227 ; Proc. Zool. Soc., 1871, p. 472. Schmeltz, Cat. Mus. 
Godeff., V, p. 89. 
Abundant on the ground in moist places, and distributed throughout the island of 
Iluaheine. 
Dr. Pfeiffer’s description agrees much better with this shell than with humeroaa, 
and, contrary to the opinion of Mr. Pease, I do not hesitate to consider my determina- 
tion as correct. The locality “ Tahiti” is too frequently used for shells inhabiting 
other islands in the group to deserve much attention. Mr. Cuming, who collected 
extensively on Huaheine, could scarcely have failed to discover so common a shell, and 
may have forgotten the exact locality. It is now well known that a large number of 
his habitats of species discovered by himself are erroneous. Mr. Pease, who was well 
acquainted with the locality of his ovata, gave the wrong one, “ Tahiti,” where it does 
not occur. 
It is more nearly related to JiuvneTosa than to any other species, but may be 
distinguished by its larger, and more produced spire, more contracted body, and light 
amber-color. Specimens with subangulated body-whorl are not infrequent, and some 
have obscure transverse sulcations. 
12 JOUR. A. N. S. PHILA., VOL. IX. 
