HELCIONISCUS. 129 



ally more obvious in the young. Broadly rayed with alternate dark 

 chestnut and soiled white or pinkish, the dark rays spotted with 

 light, the light rays with dark. 



Interior varying from bluish-white to yellow, somewhat translucent 

 and with a micaceous luster, the central area white, often outlined 

 with brown or yellow ; border colored by the dark rays of the ex- 

 terior. 



Length 85, breadth 75, alt. 33 mill. 



Length 87, breadth 74, alt. 24 mill. 



Philippines (Rve.) ; Singapore (Phil. Acad. Coll.) ; Cape Good 

 Hope (Frauenfeld.) 



P. testudinaria Linn., Syst. Nat. x, p. 783. — Hanley, Sh. of 

 Linn., p. 427. — Reeve, Conch. Icon., f. 6. — P. insignis Dunker, 

 Verb. Zool.-bot. Gesell. Wien, 1866, p. 941. — Frauenfeld, Reise 

 der osterreichischen Fregatte ' Novara' um die Erde, Zool. Theil, 

 ii, Moll., p. 14, t. 2, f. 25, 1868.— P. nmjo/iu Blainv. Diet. Sci.Nat. 

 xxxviii, p. 95, (1825.) 



A large solid species, nearly smooth, rayed and curiously spotted 

 with brown and whitish. 



H. TAHiTENSis Pcasc. PL 67. figs. 4, 5, 6, 7, 8. 



Shell conical, rounded-oval, the apex erect, and situated within the 

 middle third of the length. Slopes but slightly convex. Surface 

 sculptured with closely granulose lirulse, indistinctly alternating in 

 size. Color dusky, with indistinct reddish zigzags ; but if held to- 

 ward the light a beautiful pattern of distinct reddish zigzag stripes 

 on a light ground, is seen. 



Interior silvery-blue, the central calhis white in front, becoming 

 indistinct and leaden posteriorly. 



Length 34, breadth 30, alt. 11 mill. 



Tahiti. 



Tectura tahitensis PsE., Amer. Journ. Conch, iv, p. 98, t. 11, f. 21, 

 (1868.) 



Decidedly more erect than P. sagittaia, with coarser radiating 

 lirulse and diflferent coloring. It is more coarsely sculptured than 

 P. amussitata. Fig. 8 represents the color-pattern as seen by look- 

 ing through the shell. 



The zigzag or v-shaped markings are much broken in one spec- 

 imen before me (fig. 7), and there are several broad red dashes on 

 one side. A large series would doubtless show further variations 

 and interruptions of the typical pattern. 9 



