20 PALEONTOLOGY OF NEW YORK. 



Facial Sutures very rarely discernible. Occasional examples, in unusually 

 perfect state of preservation and favorably weathered, or compressed in such 

 manner as to slightly separate the eephalon along these lines, show that they 

 take -their origin on the lateral margins just in front of the genal angles, pass 

 along the posterior edge of the visual area, thence forward along the margin 

 of the palpebrum, following the frontal furrow of the glabella until they 

 meet, thus taking the normal direction for the facial sutures in the Phacopida. 

 It is probable thai tin' separate parts of the eephalon, in all stages of growth; 

 are virtually anchylosed along these lines, as the cheeks are rarely, if ever, 

 found detached. 



Glabella large, gibbous, filling all the space between the palpebral lobes, 

 and separated from them l>y deep furrows. Outline sub-pentagonal; greatest 

 width anteriorly. Transverse lateral furrows three on each side, of which 

 the first two are obsolescent, often discernible only on casts of the under 

 surface. In well-preserved specimens their existence is indicated by obscure 

 depressions in the ornamentation of the surface. The third pair of trans- 

 verse furrows is very strong, extending entirely across the posterior limb 

 of the glabella, making a narrow annulation in front of the occipital ring. 

 In favorably preserved specimens there are faint indications of short, longi- 

 tudinal furrows parallel to the ocular sulci, and in front of the first pair of 

 transverse glabellar furrows. 



Cheeks abruptly sloping to the margin nearly in a, plane with the visual " 

 area, narrowing anteriorly and reflected ventrally to form the doublure. 

 This doublure or infolded margin is broad at the genal angles, narrowing 

 somewhat beneath the eyes, thence forward, widening beneath the glabella to 

 form the broad depressed epistoma. A strong sulcus passes along the doub- 

 lure just below the margin, widening into a broad groove upon the epistoma, 

 and toward the genal extremities its margins bear five or six crenulations 

 which bee, une finer as they approach the angles. 



Eyes prominent, scarcely reaching the height of the glabella in uncom- 

 pressed specimens. Palpebral lobe strong, scarcely as high as the palpebrum 

 and extending to the occipital furrow. Palpebrum crescentic. Visual area 



