MoUusca of the Arabian Sea, &c. 85 



DrilUa theoreta *, sp. n. (PI. I. fig. 2.) 



D. testa mediocri, eleganter fusiformi, albo-purpurascente ; atifracti- 

 bus 10|, quorum apicales 1| vitrei, globosi, laeves, caeteris fortiter 

 et longitudinaliter rotundi-costatis, costis ultimiim ad aufractutn 

 in Tiumero decern, uudique spiraliter arete filo-liratis, superficie 

 ad suturas brunneo maculata et hie illic ad liras eodem colore 

 sparsa ; apertura ovato-oblonga, intus purpureo-fusca, vel, in- 

 terdum, albescente ; labrc baud multum incrassato, sinu excavato, 

 late ; columella recta ; canali breviter producto. 



Long. 22, lat. 6 mm. (sp, maj.). 



„ 15, ,, 4"50 mm. (sp. min., forma albescens). 



Hah. Henjam Island, Persian Gulf^ 20-25 fathoms, and 

 Sheik Shuaib Island, one large form. 



Several examples. An attractive form, showing no varia- 

 tion in sculpture, but some in coloration and size. The albino 

 variety is smaller and unicolorous, being of a pale ochreous 

 externally, with white aperture ; the normal state exhibits a 

 purplish suffusion both externally and within, and scattered 

 dots and maculations along the spiral lirse which surround 

 the shell, especially prominent on tlie ribs of the last whorl. 

 The whorls in all are ten to eleven, the apical being glassy 

 and globular, the remainder are strongly longitudinally 

 ribbed, the ribs numbering ten round the last whorl. The 

 aperture is ovate-oblong, within purplish fuscous, in the 

 normal examples -, lip not much thickened, sinus wide, 

 columella straight, canal shortly produced. 



Mangilia chilosema f, sp. n. (PI. I. fig. 3.) 



M. testa parva, turrita, albo-straminea ; aufractibus septem, quorum 

 tribus apicalibus subvitreis, delicate sub lente striatulis, CcTeteris 

 quatuor ventricosulis, apud suturas miiltura impressis, longi- 

 tudinaliter rotundi-costatis, costis ultimo in anfraetu ad undecim, 

 undique spiraliter rudi-liratis, ad suturas et apud anfractus ultimi 

 medium rubro-sparsis et interrupte zonatis, dorsaliter ad medium 

 labri conspicue rubro-maculato ; apertura oblonga, intus uni- 

 maculata; labrocrassiusculo; sinu lato,conspicuo; columella recta; 

 canali truncate. 



Long. 6, lat. 2 mm. 



Hah. Karachi and along the Mekran coast ; abundant in 

 certain localities. 



Shell small, turreted, whitish straw-colour ; whorls seven, 

 inclusive of the three vitreous, obscurely delicately striate, 



* OecoptjTos, couspicuoiis. 



t x^''^°^> ^h*' ^^'^ ^nn-'h mark. 



