NO. 7 PTYCHOPARIID TRILOBITES — RASETTI II 



Surface of test finely and densely granulated, showing in addition 

 scattered larger granules. Of these, four pairs are symmetrically 

 placed on the glabella. The surface of the internal cast appears punc- 

 tate and shows faint anastomosing ridges on the preglabellar field. 



Cranidia range from 8 to 20 mm. in length. This is the largest 

 Lower Cambrian ptychopariid known to the writer. 



Remarks. — The present form agrees with Antagmus typicalis in all 

 characters observable on its holotype cranidium, which, however, is 

 too poorly preserved to show specific features. Hence it would be 

 improper to attempt identification with that species, and a new name 

 is proposed. 



Occurrence. — Boulder B-5, Bic (type locality) ; also boulders G-i, 

 G-9, and G-15, Grosses Roches. 



T^r/'^.y.— Holotype : U.S.N.M. No. 123853. Paratypes: U.S.N.M. 

 Nos. 123854-5. 



ANTAGMUS ELONGATUS Rasetti, new species 

 Plate 2, figures 11-16 



Available material. — A dozen well-preserved cranidia and one free 

 cheek. 



Description. — Glabella relatively long and narrow, rounded in front, 

 slightly tapered, with slightly concave sides, rather strongly convex 

 transversely, moderately convex longitudinally. Second, third, and 

 fourth pairs of glabellar furrows short, rather shallow ; occipital fur- 

 row well impressed, occipital ring relatively long (sag.), bearing a 

 node. Frontal area of same relative length (sag.) as in the type species, 

 on the average horizontal medially, downsloping at the sides. Border 

 wide medially, where a rearward expansion deflects backward and 

 almost obliterates the marginal furrow ; tapering at the sides on ac- 

 count of the strongly curved anterior outline of the cranidium. Pal- 

 pebral area moderately convex, on the average slightly upsloping, 0.55 

 times as wide as the glabella at its midpoint. Ocular ridges wide and 

 low, slightly curved; palpebral lobes elevated, narrow, set off by a 

 distinct palpebral furrow, situated slightly back of the level of the 

 glabellar midpoint ; length of palpebral lobe 0.44 times the glabellar 

 length. Distance from posterior end of palpebral lobe to posterior 

 margin slightly less than length of palpebral lobe. Posterior limbs 

 as wide (tr.) as occipital ring; furrow deep and wide, reaching the 

 end. Anterior facial sutures divergent in front of the eyes, convex 

 outward, gradually curving inward and widely rounding off the an- 

 terior angles of the cranidium. Free cheek attributed to the species 



