88 Xortli American 



the first pnir arc two small complementar}' lobes, with four pustules on the 

 summit of eacli ; opposite the second pair, on each side a transversely elon- 

 gated tubercle with a tnfid crest; opposite the first pair a similar tu- 

 bercle with a bifid crest ; the ornaments on the posterior half of the gla- 

 bella being consequently arranged in three transverse series, in the poste- 

 rior of which are ten elevations, in the middle eight, and in the anterior six ; 

 the anterior half of the glabella is covered by pustules somewhat promiscu- 

 ously arranged, and var3ing in different specimens. E^^es large, globoid, 

 slightly excavated by the palpebral lobe of the fixed cheek, situated oppo.site 

 the posterior third of the glabella. Occipital ring broad, with its posterior 

 margin elevated nearly as high as the posterior extremity of the glabella, 

 and ornamented with a row of small, raised points turned backwards. 



" The pygidium ver}^ convex, semi-ellipiic, the axis very prominent and 

 forming about cme-third the width at the anteiior margin ; consisting of 12 

 or 14 rings each bearing six small tubercles, the whole of wiiich are arranged 

 in six longitudinal rows ; the tubercles often worn down on the exterior of 

 the test, but always well defined in the cast; lateral lobes bent rather ab- 

 ruptly downwards, having 10 ribs, which become indistinct and disappear 

 towards the margin, and are entirely wanting over the narrow space behind 

 the axis ; the anterior libs showing a faint median groove t(twards their 

 vanishing extremities, and a few of the posterior ones bearing feeble tuber- 

 culations towards their axial extremities." 



Ge-(jlogical position and locality, from the base of the Burlington limestone, 

 Burlington. Iowa. 



PHILtlPSIA STEVEXSONI, Meek. 



Plate 8, Y\z. G. 



Phillipsia t<tercnsoni, Meek, 1870, 3d Ann. Rept. Board of Regents of West 

 Virginia University, p. 78. 

 This species was founded upon the glabella and pygidium. which Mr. F. 

 B. Meek compares with GriffitMdes Portloddi. Meek and AYorthen. The 

 author remarks that the pygidium " is proportionately longer, more convex, 

 and more narrowly rounded behind," than that of Griffithides Portlockii ; 

 its lengtli and breadth being very nearly or quite equal, and its height half 

 the breadth. Its lateral lobes also slope more abruptly to the margins, 

 which are not flattened, but very slightly thickened, obscurely striated, and 

 abruptl}'^ sloping. It likewise shows no traces of either the furrows or gra- 

 nules seen on the anterior segments of the lateral lobes of GriffitJiides Port- 

 lockii, the surface of these lobes being entirely smooth, excepting minute 

 pitting or punctures. Its prominent mesial lobe is flattened or slightly fur- 

 rbw^ed on each side, and shows fourteen segments, ornamented each by a 

 row of small granules ; while each lateral lobe has ten less strongh- defined, 

 .*>Aind inore^epressed segments, separated mereh' by slighj: linear furrows." 

 ,^ • , ♦ ""^^he fragment of a glabella found associated with the pygidium above 



