130 HELCIONISCUS. 



H. SAGITTATUS Gould. PL 65, figs. 89, 90, 91, 92. 



Shell depressed, rounded-oval, the apex curving forward, situated 

 at about the front fourth; surface closely sculptured with radiating 

 striae, which are granose in front, usually less so behind. " Color 

 dusky olive-green, with obscure radiations of dusky ; but if held up 

 to the light the whole shell is found to be most beautifully reticulated 

 and radiated with arrow-head dusky spots, often articulated with 

 whitish." 



Interior blue or bluish-white, the central callus orange in adults, 

 yellowish-green in the young, its outlines not sharply defined. 



Length 38, breadth 34, alt. 13 mill. 



Length 39, breadth 36, alt. 9 mill. 



Viti and Fiji Islands, 



P. sagittata GLD., Proc. Bost. Soc. K H. ii, p. 148, July, 1846 ; 

 U. S. Expl. Exped. Moll. & Sh., p. 337, atlas, f. 449. 



A rounded-oval, depressed and arched species, having finely 

 granose radiating lirulse. The coloring is dusky, indistinctly pat- 

 terned, but if held toward the light an elegantly figured design 

 is seen. There are usually separated narrow radii of alternate dark 

 and light, the intervals variously reticulated ; but these articulated 

 rays are often lost in the general dusky net-work. 



This species differs from P. amussitata in having the apex more 

 anterior, the ribs finer, the pattern of coloring different. It is not 

 so elongated as P. toreuma and differs in color-pattern and sculpture. 



H. REYNARDI Deshayes. PI. 66, figs. 94, 95. 



Shell ovate, thin, fragile, depressed, radiately striated, strue un- 

 equal, subgranose ; apex obtuse ; margin entire ; interior pearly, 

 central disc white ; outside having radiating reddish-brown bands. 



Length 50, width 40 mill. (Z>/i.) 



Ceylon. 



P. Reynaudi DH., in Belangers' Voy. aux Indes-Orientales, Zool., 

 p. 411, atlas t. 2, f. 11, 12 ; DH. in Lam'k., vii, p. 543. 



H. FLEXUOSUS Quoy & Gaimard. PI. 66, figs. 96-98. 



Shell small, fragile, orbicular, angulate, arcuate, the vertex only 

 elevated; margins flexuous, obsoletely striated, whitish-brown 

 dotted, apex rosy ; inside bluish, cavity orange. 



Length 10 lines. (. & .) 



Island of Vanikoro. 



P. ftexuosa Q. & G., Voy. de 1'Astrol. iii, p. 344, pi. 70, f. 9-11. 



