164 THALESSA. 



P. MELONES, Duclos. PI. 47, fig. 56. 



Dark chestnut, vainegated with white, especially upon the 

 periphery and inferior portion of the bod}^ ; columella tinged 

 with pink ; outer lip frequentl}^ black-bordered. 



Length, 1-5-2 inches. 



Pacific Coast of Central America, 



The want of nodules or spines disagrees with the character of 

 the group ; yet the relationship of this species with P. deltoidea 

 is tolerably close. Sometimes the body-whorl is, in adults, con- 

 stricted around the middle. Morch describes the animal in 

 Mai. Blatt., vii, 99. 



P. TRIANGULARIS, Blaiuv. PI. 47, fig. 57. 



White ; more or less stained with light brown externall}^ 

 Length, 1 incli. 



Mazatlan to Panama. 



Something like P. Iriserialis, but differs in the equal develop- 

 ment of the second I'ow of revolving tubercles. 



P. MANCiNELLA, Liuu. PI. 47, tigs. 59-(jl, 63, 64. 



Shell yellowish, the tubercles frequently tinged with red ; aper- 

 ture varying from white (P. echinata ) to deep yellow ; in the latter 

 with the raised interior revolving lines darker colored (typical). 



Length, l-5-'2-5 inches. 



Bay of Muscat ; Singapore; Fiji Isles ; W. Coast Ventral 



America ; Peru ; Japan ; Australia. 



The more elevated and more sharply tubercled forms, white 

 without and within, are called P. <?e/i<rmto (fig. 63), and might 

 continue to be so designated as a variety, but the intermediate 

 gradations are very complete. P. segrota^ Reeve (fig. 64), said 

 to inhabit the waters of Japan and Australia, is one of these 

 intermediate forms. 



P. LUTEOMARGiNATA, Moutrouzicr. PI. 47, fig. 62. 



Yellowish white, the nodules chocolate ; margin of lip and 

 columella tinged with orange. Length, 1-6 inches. 



New Caledonia. 



This may be a mere variety of the preceding species, but has 

 relationships with P. bimacvlata also. 



