ASTKAl.ir.M. U;)! 



Synonyms: Stella (Klein) II. and A. Adams, L858, (type s .1. 

 aatn'ixcnA Rve.), Calcar Montfort, 1*10, (tvpe, .1. c.i/nir I /inn.?) 

 and ( 1 arinia*'a. Tenison-Woods, not Swainson. 



There lias been considerable diversity of opinion regarding the 

 group above defined, both as to its contents and its proper designa- 

 tion. Stella was the first name proposed for it ; but since, the no- 

 menclature (almost) universally adopted by /oologi.-ts dates from 

 the publication of the tenth edition of Linmeus ( 17-VS), \\e are com- 

 pelled to reject the names proposed by Klein in 17-").'). This course 

 is rendered the more imperative by the nature of Klein's work ; for 

 his "genera" are as often denominated by a phrase as by a single 

 word. Calcar of Montfort was probably founded on a species of 

 this subgenus. But this is very uncertain, as his figure might be- 

 long to anyone of several very different forms. (See also "Fischer, 

 Man. de Conch., p. 813.) As to Carmidea Swains., which Tenisoii- 

 Woods has supposed to include the group of A.fimbrialurn, A. ten- 

 toriifonne etc., there is no warrant for using it in any sueh sense; 

 for Swainson's two types are (1) an innbllieated species of Trochus, 

 and (2) a species of Uvanilla, (A. buschii Phil.). Hercoles Montf. 

 referred to this group by some authors, is not a mollusc. As to the 

 limits and contents of Cyclocantha as here defined, I am aware that 

 there is room for controversy. Fischer and others have distributed 

 a portion of the species among several adjacent subgeiiera. I have 

 included with considerable hesitation A.fimbriatum and A. tvniorn- 

 fornie ; but I do not think that they would be any better placed 

 with J. olivaceus etc. in Uvanilla. 



It is very difficult to express in a diagnosis the differences be- 

 tween the shells of this group and of Astralium, x. s. Both contain 

 flattened wheel-shaped umbilicate forms, with long peripheral 

 spines, and both have compact trochiform species. The two groups 

 occupy almost opposite areas upon the globe. 



A. CALCAB Linn., 1758. PI. 52, figs. 27, 29, 30; PI. 56, fig. 74. 



Shell conoid, more or less depressed at apex; grayish greenish, 

 or brownish cinereous; whorls 6, flattened above, and radiately pli- 

 cate, the folds rather unequal and irregular; periphery carinated 

 spinose, bearing about twelve radiating more or less foliated spines 

 upon the body-whorl ; last whorl deeply descending toward the 

 aperture ; base convex, concentrically more or less densely squa- 

 mosely lirate, the outer line generally prominent and subspinose, 

 sometimes causing the periphery to appear hie:- .ate; aperture 



