GEOLOGICAL SURVEY OF THE TERRITORIES. 483 



rather well defined by the dorsal furrows, about twice as long as wide, 

 with the anterior end sometimes apparently very slightly expanded; 

 neck segment projecting somewhat backward, rounded in outline behind, 

 and nearly as high in the middle as the glabella in front of it ; neck 

 farrow narrow, rather well defined, passing entirely across, and continued 

 much wider and deeper across the posterior margin of each cheek; lat- 

 eral furrows consisting of four pairs, the posterior pair commencing a 

 little behind the middle and extending very obliquely backward and 

 inward to a point about the breadth of the neck furrow in advance of 

 the same, where they either become obsolete, .or apparently sometimes 

 almost connect across by a shallow transverse furrow ; succeeding 

 pairs in front very short and transverse, the anterior ones being some- 

 times rather obscure ; fixed cheeks moderatelj^ wide, or equaling, at the 

 posterior end of the eyes, half the breadth of the glabella opposite the 

 same i)oint, rather convex, but lower than the glabella; palpebral lobes 

 very narrow, or merely appearing as little slightly raised rims at the 

 margins of the fixed cheeks, from which they are separated by a linear 

 furrow. Eyes, as determined from the palpebral lobes, about two-thirds 

 as long as the breadth of the glabella, slightly arched, and somewhat con- 

 verging foTward, situated their own length in advance of the posterior 

 margin of the head, and two-thirds this distance at their posterior ends 

 from the glabella. Facial suture in front of the eyes unknown, but 

 behind them, directed at first for a very short distance nearly backward, 

 then curving abruptly outward, parallel to -the posterior margin of the 

 cheeks, and extending nearly to the posterior lateral angles, where they 

 curve obliquely backward and outward so as to cut the posterior mar- 

 gin near these angles. 



Thorax consisting of nine segments ; axial lobe very narrow, or only 

 about two-thirds as wide as each of the lateral, tapering gradually back- 

 ward, and moderately convex ; lateral lobes flattened, and lower than 

 the axial ; pleurse broadly and deeply furrowed', and having their free 

 ends apparently falcate. 



Pygidium intermediate between semicircular and semielliptical, its 

 length being about two-thirds its breadth, while its posterior margin is 

 rounded in outline, and its anterior nearly straight across; mesial lobe 

 as narrow, proportionally, as that of the thorax, convex, tapering very 

 gradually backward, and nearly reaching the posterior border, showing 

 five or six well-defined segments, with space enough for one or two 

 more behind those ; lateral lobes flat, with five or six broadly furrowed 

 segments that extend to, but not upon, a very narrow, slightly thickened 

 and flattened, smooth margin. 



Entire surface smooth, or only showing very fine granulations under 

 a magnifier. 



Length of an entire specimen 1.15 inches, breadth about 0.70 inch. 



Although I refer this species, provisionally, for the present, to the 

 genus Bathyurus, I really do not think that it properly belongs to that 

 genus, as illustrated by the typical species B. extans. In the propor- 

 tional size of its head, thorax, and pygidium, as well as in the number 

 of its body segments, it agrees with that genus ; and its glabella, though 

 narrower and more strongly as well as somewhat diiierently lobed, is 

 not otherwise very different; while, so far as known, its facial sutures 

 seem to agree in most respects. The general flatness of the whole ani- 

 mal, however, as well as the narrowness of its axis, and particularly the 

 different type of its large rounded pleural furrows, (those of B. extans 

 being narrow and regular,) are strongly marked features, which, with 



