TKII.olUTI 717 



;.- .....l.l 



lieneral form ovoid, broade-t anteriorly, attenuate and salient at (lie angles of 

 the cephaloti. Axial length ami: \\ hit h equal. < 'ephalon l.roa<lly semicir 



cular on the anterior margin, slightly incurved or contracted laterally ami again 

 prominent at the geual angle- which arc narrow ami produced beyond the general 

 outline of the body into lilunt. short spines. Posterior margin gently convex on the 

 cheeks and much more convex axially. Dorsal furrows clearly defined on the 



rior half of the cephahm. disappearing at or in front of its summit. On internal 

 casts these furrow- are quite, deep and though becoming faint anteriorly may some- 

 times be traced nearly to the front margin of the shield. The glabella thus outlined 



il)i|ti:idrate. expanded anteriorly. it.- meilian width being about one-third the 

 entire width of the cephahm. \Vhere faintly delimited on its anterior portion its 

 width is one third greater than at it- ba.se. A single pair of very short lateral 

 glabellar furrows makes a slight indentation on each margin, serving to divide 

 the part into an anterior or frontal lobe and a single pair of lateral lobes. The 



.'ital furrow and ring which are scarcely discernible on the outer surface are 

 dearly di-tinguishahle upon the cast. The anterior slope of the glabella is deep, 

 nearly vertical for a short distance and convex above. The fixed cheeks are less 

 convex than the glahella and along the dorsal furrows on the cast, bear an indenta- 

 tion opposite and corresponding to the lateral lobes of the glahella. The general 

 surface tapers to the narrow, siibcvlimlrical palpehral lobes which are depressed 

 below the re->t of the surface and lie nearly in the plane of the thorax. The free 

 cheeks are abruptly constricted beneath and in front of the eyes and take the form 

 of di\ rrj^ent .-lightly recurved -pines or horns. The facial -utures rise rapidly from 

 the occipital margin to the summit of the eye-nodes, thence rounding gradually 

 forward to the anterior margin which they intersect opposite the anterior extremities 

 of the dorsal fun-' 



Fig. 25. Internal cast of Thaleopt ovata Conrad. 



Thorax subquadrate, tapering; composed of ten segment-. Surface strongly 

 lobed. Axis convex, narrow. I'leuni* geniculated at about one-third their length. 

 Segments Hat and. upon the axis, moderately broad, not furrowed on the pleur.e. 

 recurved toward their extremr 



