126 Mr. A. Adams on Gasteropodous Mollusca 
= apertura subquadrata, plica parietali conspicua, trans- 
Hab. Gulf of Suez. 
Most nearly resembles S. pyramidalis, A. Ad., but is not 
umbilicated. It is also like Ob. vitrea, A. Ad., but is without 
any coloured red band on the whorls. 
Genus ORINA, A. Ad. 
Testa vitrea, conico-turrita, umbilicata ; anfractibus planis, simpli- 
cibus. Apertura subquadrata, plica parietali unica transversa 
instructa, 
O. pinguicula, A. Ad. 
O. testa conoidali, profunde Rr alba, tenui, levi; anfr. 
norm. 5, planis, suturis can atis ; den. "ribquaiia 
antice subangulata ; plica pariak transversa, valida ; labro intus 
transversim sulcato 
Hab. Gulf of ka 
Like a short umbilicated Syrnola. S. pyramidalis, A. Ad. 
(Ann. & Mag. Nat. Hist. 1860) also belongs to this newly 
indicated sa 
Genus STYLOPTYGMA, A. Ad. 
1. S. lendix, A. Ad. Proc. Zool. Soc. Lond. Nov. 1862. 
. Hab. Gulf of Suez (M'Andr.), Japan (A. Ad.). 
2. S. nivea, A. Ad. 
S. testa subulata, in medio Pagar. solida, cherie, nivea, polita ; 
anfract. norm. 6, planulatis, su uturis marginatis ; Sperm elon- 
Hab. Gulf n Suez. 
A solid, ivory-white, highly polished species, with an elon- 
gated aperture, and with the plait on the inner lip very oblique. 
Genys MONOPTYGMA, Gray. 
M. fulva, A. Ad. Proc. Zool. Soc. 1851; Sow. Thes. (Mon. 
Monopt.) pl. 172. f. 23. 
Hab. Gulf of Suez EN ; Philippines (Cuming), 
Genus MxoNA, A. Ad. 
M. casta, A. Ad. (Monoptygma), Sow. Thes. Conch. (Mon. 
Monopt.) pl pL.i7x f 3 a » 
Hab. Gulf of Suez neret China Sea (A. Ad.). 
