NO. 7 PTYCHOPARIID TRILOBITES — RASETTI 31 



furrow deeper laterally, occipital ring bearing a node or short spine. 

 Frontal area on the average concave, indistinctly divided into pre- 

 glabellar field and border. Palpebral area downsloping, narrower than 

 glabella ; ocular ridges strong ; palpebral lobes one-third as long as the 

 glabella, obliquely situated, at level of anterior third of glabella. 

 Posterior limbs with wide furrow ; posterior margin with sharp geni- 

 culation. Anterior facial sutures convergent; posterior branch di- 

 rected outward and backward without much curvature. Test coarsely 

 granulated. 



Type species. — Rimouskia typica Resser. 



Remarks. — Rimouskia differs from Sao in the less tapered, longer 

 glabella, lack of a definite sagittal glabellar furrow, straight posterior 

 branch of the facial suture, stronger and more distally located genicu- 

 lation of the posterior cephalic border. 



The genus is known exclusively from the Lower Cambrian of 

 Quebec. 



RIMOUSKIA TYPICA Resser 



Plate I, figure lo; plate 6, figures i-6 



Rimouskia typica Resser, Geol. Soc. Amer. Spec. Pap. 15, p. 98, pi. 3, figs. 20- 



22, 1938. 

 Rimouskia spinosa Resser, Geol. Soc. Amer. Spec. Pap. 15, p. 9$, pi. 3, fig. I9i 



1938. 



Available material. — The holotype and a paratype, plus several 

 additional topotype cranidia. Also the holotype of Rimouskia spinosa. 



Description. — Glabella very strongly convex transversely, almost 

 flat longitudinally excepting the anterior part which drops steeply to 

 the preglabellar field. Glabellar furrows deeply impressed on the 

 lateral thirds of the glabella, in some cranidia showing a tendency to 

 connect between the various pairs through shallow longitudinal exten- 

 sions of the furrows at their inner ends. Occipital furrow deep in the 

 lateral thirds, shallow medially; occipital ring bearing a short spine, 

 more developed in the smaller cranidia, directed upward. Sagittal 

 length of frontal area 0.30 times the length of the glabella. Concave 

 preglabellar field gradually changing into convex border. Lateral 

 portions of preglabellar field steeply inclined in front of prominent, 

 curved ocular ridges. Palpebral lobes oblique, one-third as long as the 

 glabella, elevated, set off by distinct palpebral furrows ; distance from 

 posterior end of palpebral lobe to posterior margin almost twice the 

 length of palpebral lobe. Posterior limbs 1.3 times as wide (tr.) as oc- 

 cipital ring, very broadly furrowed. Posterior border with sharp ge- 



