76 



In"this particular it differs from JV. calcar, whofe body is 

 clafped very much by the margin of the ^.nXev'xorfeptum, a 

 may be feen by a comparifon of fig. 4, Tab. I5, and fig, 

 7, 8, Tab. 1 8, This fliell is alfo diflerent in colour, is larger, 

 and the cells more numerous. 



Aperture a fmall fyphoii near the exterior angle, not pro- 

 truded. 



Calcar Nautihis rotatus. Z/w, 7Va;w. viii. p. J,14. 



p. 189 



In our former ^'«072^'ma of this flieli, it will be feen we 



had refered to Walker, and Adams, for our Calcar, with 



doubt : the light however thrown upon tlie fubjedl by the 



Boyfian cabinet, requires that thofe references fhould be 



transferred to JVaiitilus JubarcuaUdus, hereafter defcribed. 



Nothing could have induced us to have referred to Walker's 



fig. 66, for our calcar, but the authority of our late valuable 



friend Mr. Boys, who at the time of ill health did not dif- 



criminate fuch minute objects witli his ufual accuracy. 



Martini gives the figure of a JVawi/'/wi, which he con- 

 fiders as one of the varieties of the Linnceati calcar; it is 

 however perfe6tly difiin6t from our fliell. Ihat Ipecies 

 which may be conlulted in Martimi, Conch, i. Tab. 20, fig. 

 182, 183, Mr. Mead difcovered fulfil with tliofe before men- 

 tioned near Sienna, The fpecimens that we l^ave examined 

 do not much exceed a quarter of an inch in length, and 



fumewhat 



