ASTRA LHM. '_>_>] 



Like Turbo, this genus is composed of a number of quite div- 

 subgenera of various degrees of affinity to radi oilier. I am in- 

 clined to divide them first into two scries; those with tin 1 central 

 teeth of the radula composed of several plates overlying each other, 

 and without a reflected cusp at the superior margin, and those with 

 a reflected cusp above. 'The natural sei|uence and affinities of the 

 subgvncni are shown in the following table: 



( ( Astral ium. .-.-. 



Central teeth of radula j ( kithopoina, 



with cusps. ( Imperator( 



1 Guildfordia. 



Bolma. 



Central teeth of radula { Cycloeantha. 



. . (L vanilla, 



without cusps. 



i ( 'ookia. 

 I Pomaulax. 

 (_Pachypoma. 



Subgenus ASTKALIUM, Link, #. efo. 



Shell conical, elevated or depressed, narrowly umbilicate or ini- 

 perforatc, carinate at the periphery, base plan u late or convex, whorls 

 above flattened or concave, costate or tuberculate ; operculum oval, 

 outside smooth or nearly so, very convex, excavated near IIK- center. 



}\\-*t Indum 1'i'n,-' 

 Calcar Schum., 1817, is a synonym. 



A. LOX<;ISI>IXA Lam., 1822. PI. 51, figs. 1-9. 



Shell depressed conic or lens-shaped, umbilicate or impcrforate ; 

 white, 'yellowish or light brown ; apex obtuse; whorls 5-6, acutely 

 carinated at periphery, concavely flattened above, obliquely plicate 

 or spirally lirate, the line bearing tubercles or s(piam>e pro ( - - 

 periphery armed with recurved triangular obliquely wrinkled spine>, 

 usually thirteen to eighteen in number on the hist whorl, and more 

 or less projecting at the sutures ; base gently convex, densely lamel- 

 lose radiately striate, and with about four concentric subnodose lir:- : 

 aperture transversely ovate, angled and canaliculate at terminal ion 

 of carina ; columella short, curved, somewhat dilated over the slight- 

 ly indented umbilical tract ; umbilicus generally very narrow or not 

 perforated. Alt. 30, diam.'OV) mill. 



Entire West Indies ; Bahamas; Bermuda; Tortugas (Sim; 

 Guatemala. 



