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•8 



UKroKT — 1884. 



of a GoTiiatite, from the Cioniatilon-Kalk of Altcnau, in the Ilixvtz. In 

 general aiipoaraiicc the figure approaclies I'hd.'aducuriA; 



Sy\oit;cai, Plan ok thk Discinocakida. 



Sliliild witli'tiit (I mediiin 



tLirsal suture. 



(Tyi)(', Discinocarh.') 



1. Postorior iimrjiiir 



cntii'i! and rdiiiiilcil. 



I. Cepliiilic notch 

 (-^nuchal suture) 

 iin<ruliii' 



1. Shield not rid^'cd 



iKir furrowed 



2. Shield liaviiifj; ^ 



rndiatc furrows nnd iii. rnoi.AixiC'.vitis 

 ridjjos . . . ' 



II. Ceplialio notch ». j. 

 rounded. . . i 



tJ. Posterior margiir 

 iinirular ; .sli i eld 

 ■with radiate ridne<. 

 (Cephalic notch 

 rounded 



3. Posterior margin in- | 



dented; ceiihalic vi. ('AitMioc.vitis 

 noteh an,t;ular . ) 

 A. Posterior margin") 

 deeply notched ; 

 cephalic notch, 

 nni^uhir . 

 A. Concentrically 

 striate, like Disci- 

 nociiris, &c. . .J 

 II. Not concentrically 

 striat'i. 



1. Test with radiate 



ornament 



2. Test smooth ; mi- 



nute . 



notch hroad 



i. l)l.S(IN(l( AltlS 



notch iiniTuw 



ii, Si'AriiiocAUis 



I'SOCAIMS 



V. l.isiMK Ai;is 



S/iiipe nr outline of Shield 

 Species. (complete, .nnd measured 



outside the notches). 



/ Tirowniana, duhia, lata circular. 



tritisira . . . oval. 



, sp. MOV. . . . ohovate. 



\ rimiinirr . . , ohlonj;'. 



( Kmeraonii . . fihlonij. 



■j V small form . ohovate. 



\ viiguliiia , , . oval. , 



f Lveii .... cuneiform. 

 t sp. nov )hovate. 



( Dewalquei . . 



( sj). nov. 



Luth 



oval, 

 suboblonj:. 



( Jiiiiineri, hipartita 

 ( Veneris, Koeneni 



, pes-cerva', vetustu 



J pes-ren 

 . , ' nriicne 



j pciDilv-dirditlt 

 V l^tluridjii , 



viii. PncilfK AliIS hahemicn 

 ix. Citr.scKNTii.i.A piignax 



siibpcntagonal. 



narrow ohovate. 

 hroad ohovate. 



ohovate. 

 suhquadrate. 

 suhobiont^, 

 oval. 



ohovate. 

 oblate. 



As in all other natural groups, it is difficult or impossible to arrive 

 at a perfectly linear arrangement ; the order, therefore, in this plan of 

 the Discinocarids does not quite correspond with that in the foregoing 

 list of genera and species, which is followed in the descriptions. 



I. DisciNOCAKis, H. Woodward, 1806. * Quart. Journ, Geol. Soc.' vol. 

 xxii. p. r>0o ; and ' Geol. Mag.' vol. iii. 18G0, p. 71. 



This Phyllopod has a ronnd, oval, ovate, or oblnng shield, slightly 

 conical, without a median suture, but crossed anteriorly by an angular 

 nuchal suture, often leaving a corresponding notch. Concentrically 

 striate, like its congeners. 



1. Biscinocaris Jiroivniana. H. AVoodward, 18GG. ' Quart. Journ. Geol. 

 8oc.' vol. xxii. p. 504, pi. 25, figs. 4 and 7, andf. 5 side view, &c. 'Geol. 

 Mag.' vol. iii. 1866, p. 72. 'Catal. W.-Scot. Fossils,' 187G, p. 7. 'Catal. 

 Catnbr. and Silur. Foss. Pract. Geol. Museum,' 1878, p. 28. 'Proceed. 

 Belfast Nat. Field-Club,' 1877, Appendix, p. 122, &c., pi. 7, f. 25 a and 

 25 c. 



This is a circular shield, 15 mm. in diameter. Slope of nuchal 

 suture, 60° ; diameter of disk-shaped carapace, 7 lines ; width of nuchal 



