1887.] NATURAL SCIENCES OF PHILADELPHIA. 17 



both fossils under consideration must be closely related, if not 

 identical. 



The specimen, of which a figure is subjoined, has a total length 

 of 16 millimetres; length of head, 6 millimetres; length of thorax 

 with seven segments, also 6 millimetres ; length of pygidium, 4 

 millimetres. 



The head of the specimen, deprived of the movable cheeks, 

 bears a large glabella considerably dilating in front, with three 

 distinct lateral furrows. The thoracic ribs are deeply excavated 

 in the centre, and the adjoining margins of every rib project as 

 high ridges with a dividing line along the crest. The annuli 

 composing the pygidium are rather obsolete, but four sharp fur- 

 rows, spreading from each side of the rachis, indicate its compo- 

 sition of at least four anchylosed segments. 



Conocplialites cordillerse, nov. sp. Pi. i, fig. 7. 



Numerous specimens of this little trilobite occur in the collec- 

 tion ; their average size in length is about 25 millimetres ; the 

 movable cheeks of the specimens are generally missing, other- 

 wise the bodies are usually perfect. 



Glabella conical, convex, provided with three lateral furrows, of 

 which the posterior is the largest, quite oblique ; occipital furrow 

 deep. . The glabella in its extension towards the front varied 

 some, as between it and the upturned projecting rim of the front 

 a broader or narrower strip of the fixed cheeks intervenes. The 

 fixed cheeks are broad, margined with a small reniform burrelet 

 at the palpebral angle of the facial line, and from the anterior end 

 of this eye-rim a faint rugosity is seen to run across the fixed 

 cheeks, toward the front part of the glabella, near its anterior 

 sulcus. 



Rachis uniformly tapering toward the tail-end, consisting in 

 the thoracic part of seventeen segments, in the majority of speci- 

 mens examined ; but in one, evidently belonging to the same 

 species, I counted only fourteen, and in another fifteen. The 

 ribs are pretty straight, with a deep central depression and high 

 projecting marginal rims, which are joining the rims of the 

 neighboring ribs in a sharp linear groove. Each annulus of the 

 rachis at its juncture with the ribs is decorated with a rounded 

 node. 



The entire surface of the body appears, in well-joreserved 

 specimens, covered with delicate papilli and granules. 



