THALKSSA. 16H 



The adult specimen (P. Bronni\ which I figure from Lischke 

 (fig. 33), is remarkable for the confluence of the tubercles into 

 greatly raised rounded ribs on the body-whorl. P. clamgera, 

 Kiister (fig. 49 \ is a depauperate form. Reeve's locality, " Zan- 

 zibar," for P. tumulosa is probably an error. 



P. PICA, Blainv. PL 46, figs. 46. 47, 52, 53. 



Shell whitish, banded with dark chocolate; bands appearing 

 within the margin of outer lip and on columella; interior of 

 outer lip with close, narrow, raised, brown revolving lines. 



Length, l*25-2'5 inches. 



China Sea; Philippines; Central Pacific Ocean. 



Broader, more ventricose, with shorter, stouter, and more 

 direct spines than P. hippocastaneum. The want of teeth and 

 development of raised revolving ribs within the outer lip are 

 good distinguishing characters. P. cuspidata, Ad. and Reeve 

 (fig. 47), is the young. 



P. ARMIGERA, Chemn. PL 46, figs. 50, 51. 



White, generally with light brown bands between the roww of 

 tubercles ; aperture yellowish or pink within. 



Length, 2-3'5 inches. 



Philippines; Paumotus, etc. 



P. affinis, Reeve (fig. 51), is the young. The animal is described 

 fully in Gould's Moll. Wilkes' Exped., p. 245. 



P. TRISERIALIS, Blainv. PL 47, fig. 54. 



White, with revolving bands composed of brown squares ; yel- 

 lowish white within. Length, '75-l'5 inches. 



Acapulco ; Mazatlan. 



P. DELTOIDEA, Lain. PL 47, figs. 55, 58. 



Light brown or whitish, with dark chestnut bands, which 

 sometimes appear also on the inside of the outer lip ; columella 



pink. Length, '75-2 inches. 



West Indies ; Florida. 



^ery closely allied to P. triserialis; the bands are not broken 

 up into squares of color, but are continuous and much darker ; 

 the color of the columella is also different. 



P. albocincta, Kiister (fig. 58), appears to be founded on a 

 worn, immature specimen of this species. 



