TTEROPODA. 143 



20. LOBATA, f, 81, So^u erby. — y-dgma elongato-trlgona, 

 Isevi ; disco dorsali lohato ; apertura suhtrigona, laLro pro- 

 ducto, quinque-lobato, ang•uli^J lateralibus utrinqiio in spinam 

 productis, spinis acutissimis ; apice elongate acutissimo. — 

 The spines at the angles of the apertures are very sharply 

 produced ; the dorsal disc is lobed, and the margin of the 

 labrum is five-lobed ; apex very long and produced. 



21. AUSTRALis, f. 29, Orbigny. — Vagina longitudinaliter 

 trigona, lateraliter quadrigona ; disco ventrali et disco dorsali 

 medio angulatis, angulis lateralibus et apice acute productis, 

 spinis nullis. — Both discs of the vagina are angular in the 

 middle, so as to make it a four-sided figure ; the apex, side 

 angles, and point of lower disc are sharp, but not produced 

 into spines. 



22. ISFLEXA, f. 21, 22. — Parva tenuissima alba trigona ; 

 apertura trigona, utrinque ad latera in spinam trigonam pro- 

 ducta ; vagina gradatim angustata, apice elongato, retrorsim 

 uncinato. — Very small, transparent, and triangular, with pro- 

 duced triangvdar spines at the angles of the three-cornered 

 aperture. 



23. DEPKESSA, f. 25, 26, Orbigny. — Minuta alba hyalina, 

 arcuatim depressa, apertura utrinque ad angulos profunde 

 incisa, in spinam utrinque producta, marginibus productis, 

 fere iequalibus tortuosim acclivibus ; apice acuminato, de- 

 flexo. — Resembling CI. infiexa, but with the upper disc 

 flattened in the middle, and the two lips of the aperture 

 nearl}' equal and curved upwards. 



Genus BALANTIUM. 



24. KECURYUM, f. 35, 67i/7(Zrc?t.— Subcompressa, late suh- 

 trigona, concentrice tenuiter rugata; dorso lobato ; apertura 

 semihmari ; labro paulo producto, lobato ; lateribus angu- 

 latis, subconvexis, ad aperturam acutis ; apice in spinam 



