ASTRALIUM. 



221 



Like Turbo, this geiuis is composed of a number of quite diverse 

 subgenera of various degrees of affinity to each other. I am in- 

 clined to divide them first into two series : those with the 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 sequence and affinities of the 

 subgenera are sliown in the following table : 



f f Astraliuni, s.s. 



Central teeth of radula \ ^ ^ 



with cusps. I ^ Imperator. 



t 1 Guildfordia. 



Central teeth of radula 

 without cusps. 



<. Bolma. 



( Cyclocantha. 

 I U vanilla. 



r Cookia. 

 -] Pomaulax. 

 (^ Pachypoma. 



Subgenus Astralium, Link, s. str. 

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

 perforate, carinate at the periphery, base planulate or convex, whorls 

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

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



West Indian Province. 

 Calcar Schum., 1817, is a synonym. 



A. LONGispiNA Lam., 1822. PI. 51, figs. 1-9. 



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

 Avhite, yellowish or light brown ; apex obtuse ; whorls o-Q, acutely 

 carinated at periphery, concavely flattened above, obliquely plicate 

 or spirally Urate, the lirse bearing tubercles or squamose processes ; 

 periphery armed with recurved triangular obliquely wrinkled spines, 

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

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

 lose radiately striate, and with about four concentric subnodose lira3 ; 

 aperture transversely ovate, angled and canaliculate at termination 

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

 ly indented umbilical tract ; umbilicus generally very narrow or not 

 perforated. Alt. 30, diam. 65 mill. 



Entire West Indies; Bahamas; Bermuda; Tbrf tty as (Simpson) ; 

 Guatemala. 



