No. 4.] 



BILI.1NU8 ON fOUISILP. 



2'd'S 



inolioB in Iciifrth, uie.'isured along all the curves. It is 15 lioe^ 

 in diuiiiuUr at 5 inches from tiie bii8e, and about 18 lines at the 

 cup. The Beptul castas are very di.stinctiy defined at the ba.se 

 but become more flattened and obscure upwards. In external 

 characters it resembles .1. exilis, but the much greater dcTelope- 

 inent of the wpt i distinirui.shos it therefrom. 



To A. miriihUit, I add, provisionally, a specimen which whea 

 perfect, mu-'t have been 2 feet in leni^th. It is 17 Hues in 

 diameter at the calice and about 11 lincH at 12 inches below 

 There are about If) larj^'e septa at the base of the cup, with an 

 0(|ual number of bmaller ones. Depth of the larger, 3 to 5 lines, 

 and of the f-nialler, 1 or 2 lines. As in the former specimen all 

 the nepta are more or less curved. 



Both fpecimens occur in the C«»rniferous. 



Genua ZAi'iniK.NTis. 

 • 4. Z. INVRNTST.A. — (.'onillum somtwhat slender, expanding 

 to a diameter of 16 lines in a length of 1 inclies. Surface with 

 numerous roumled rings of growth, of all sizes up to 3 lines in 

 width. Cost il stria) about 8 in the widtli of 3 lines, where the 

 dianjeter is 10 or 12 lines. Where the diameter is 15 linn 

 there are about 50 large and the same number of sninll septa. 

 The larger have a depth of about 5 lines and the smaller 4 linos. 

 They .seem all to be slightly flexucMis at their inner edges. The 

 cup is about 1 inch in depth, the bottom smooth, flat or slightly 

 concave and 4 lines wide. There is a small septal fobsette. 

 Occurs in the Corniferous. 



5. Z. Kru'IIVI.k. — (,'orallum turbinate, slightly curved, ex- 

 panding to a wiilth of 2 inches in ;i length of about 4 inches, 

 i^urfice with numerous .snjall, mostly «liarp-edged rings of growth. 

 Near the base there are 7 or 8 costal striae in tlie widtli of 3 

 lines; near the cilice there appear to b'' 4 or 5. There are 

 about (10 large septi, at a diiimeter of 2 inches. Many of these 

 extend inwards to the centre. There are also 60 small septa, of 

 u deptli of from 5 to 7 lines. Bott(»ni of the eup nearly flat, 

 ibout 10 lines wide. The septal fossette i.s of an ovate form, its 

 outor edge not reaching the margin, iis inner extremity about 

 half way to the centre. 



This sp'-'cies is allied to X. iuvenintn in having about the samt 

 numbers of septa in the same wiilth. It differs in having a 

 uiueh greater diameter, and the large .septa reaching the centre^ 

 Occurs in the (Jorniferous. 



