CALLIOSTOMA. 387 



{Group of 0. millaris Brocc.) 

 C. MiLiARis Brocchi. PL 18, figs. 10, 11 ; pi. 15, figs. 41, 42. 



Shell strictly conical, imperforate, rather thin, but pretty solid, 

 whitish or yellowish, with more or less obvious longitudinal flames, 

 often reduced to a few spots on the ribs and a row of spots at the 

 periphery of each whorl. Surface densely finely sculptured by spiral 

 lirce crossed by very regular oblique lamellce, producing a clathrate 

 patt rn, spirnl lira? about 6 in number on each whorl, but often 

 double as many, by the intercalation of ribletsin the interstices. The 

 periphery has a prominent keel, cord-like, with secondary spiral stride, 

 or bifid, cut into compressed granules, somewhat prominent above 

 the sutures. The base has about 8 concentric ribs, interstices 

 radiately striate, sometimes with a central riblet. Spire conical ; 

 periphery acutely angled, base flat. Whorls about 7, aperture quad- 

 rangular, columella short, nearly straight. Alt. 13, diam. 13 mill. 



Mediterranean and Adriatic Seas; Atlantic Ocean,, Norway to 

 Gibraltar ; Cape Verde Is. ; Miocene of Vienna, Italy, etc. 



Tr. millaris Brocc. Conch, foss. Subap., p. 353, t. G, f. 1 (1814). 

 — Rrsso, Eur. Merid. iv., p. 130. — Philippi, Conchyl. Cab., p. 71, 

 t. 13, f 19. — BuQ. Dautz. and Dollf., Moll, du Rouss., p. 357, 

 t. 42, f. 20-25. — Trochus martini Brown, 111. Couch. Gt. Brit., p. 

 129, t. 57, f. 11 (1827).— Thorpe, Brit. Mar. Conch., p. 164, t. 3, f 

 36. — Tr. millegranus Philippi, Enum. Moll. Sicil. i, p. 183, t. 10, f. 

 25 (1836) ; Conchyl. Cab., p. 88, t. 15, f 9. — Jeffreys, Brit. Conch, 

 iii, p. 325 ; v, p. 204, t. 63, f. 4.— Fischer, Coq. Viv., p. 146, t. 49, 

 f. 1. — Conulus millegranus Phil., Sars, Moll. Reg. Arct. Norv., p. 

 143, t. iv, f. 3 (Dentition). — Ziziphinus millegranus Phil. Brusina, 

 Contr. pella Fauna Dalm., p. 79. — T. clelandi Wood, Ind. test, 

 suppl., t. 5, f. 15. — T. clehmdianis Leach, Synops. Moll. Gt. Brit., 

 p. 172. — T. elegans Jefp^r., teste Jeffreys. 



The clathrate sculpture is very characteristic. 



( Group of C. zizyphinum Linn.) 



The Mediterranean species of Calliostoma immediately allied to 

 C. zizyphinum form a group very closely allied in characters, and 

 at the same time each species is excessively variable. The char- 

 acters common to the group are the straightly conoidal outline, gran- 

 ulate upper whorls, the lower ones polished and either smooth or 

 spirally sulcate. The following species are included: zizyphinmn, 

 conulam, gaalterianum, laugieri, etc., each with numerous synonyms.. 



