Land- Shells of the Stilu Archipelago. 53 



6. Trochomorpha Metcalfei^ PfeiflFer. 



Helix Metcalfei, Pfr. Conch.-Cab. ed. 2, p. 175, pi. xcvii. fiprs. 10-12, 

 var, fifrs. 13, 14 ; Deshayes, Illst. Nat. Moll. vol. i. p. 307, pi. ci. 

 lijr^. 10-12. 



Hvlix solarioides, Reeve, Conch. Icon. pi. xxx. figs. 127 a-c. 



IMir hoholeiisis, Semper, Hidalgo, Joiim. do Conch. 1887, pi. iv. 

 figs. 1-1 a. 



Hob. Tawi-Tawi, Bongao, Bilatan, Sibutu. 



Two forms of this species occur at the above islands. One 

 resembles that represented by PfeifFer's figures 10-12 and 

 Reeve's figures 127 &, c. The specimens, however, are 

 smaller, and the brown zones above and below the periphery 

 are narrower and less pronounced. The diameter of average 

 specimens is 15 millim. This variety occurs at all four of 

 the above islands. The other form, which occurs at Bilatan, 

 Bongao, and Sibutu, is similar to that figured by Pfeiffcr 

 {I. c. figs. 13, 14) and by Reeve (fig. 127 a). The specimens 

 are a little smaller than those just referred to, of a pale 

 greenish -yellow tint, and the keel is of a very deep brown- 

 black colour, like the narrow zones above and below, which, 

 togctlicr witli the carina, form one dark ]ieripheral zone. In 

 the Philippine examples figured by Pfeiffer the keel is 

 whitish { = boholensiSf Semper). Mollendorflf is of opinion 

 that there is sufficient difference between Metcalfei and hohol- 

 ensis to distinguish them, but with this opinion I cannot 

 concur. 



7. Helix {Plectotropis) squamulifera^ Mollendorff. 

 (PI. IV. figs. 3, 3 a.) 



Helix (Plectotropis) squamuUfera, Mollendorff, Jahrbuch. deutsch. 

 mal. Gesell. 1887, p. 290. 



Hob. Bongao {Molldf & Everett) ; Sibutu {Everett). 



The specimens described by Mollendorff" were immature, 

 and consequently he could not complete the description of the 

 peristome. It is pinkish white, scarcely thickened at all, 

 slightly expanded above and somewhat reflexed below. The 

 largest example is 15 millim. in diameter, but an average 

 specimen is only about 13. 



8. Helix [Chloritis) sihutuensis. 

 (PI. IV. figs. 4, 4 a.) 



Testa dcpresse globosa, anguste umbilicata, subsolida, rufo-fusca, 

 linea saturatiore ad periphcriam cincta ; anfractus 5, leviter con- 

 vexi, apicales concinne puiictati, caiteri linois incrementi tcnuibus 

 striati, indistincte punctati, ultimus antice vix descendens ; aper- 



