NO. 7 PTYCHOPARIID TRILOBITES RASETTI 1 9 



frontal area average for the genus ; border prominent, highly convex ; 

 marginal furrow regularly curved, with but a trace of a median in- 

 bend. Palpebral area 0.8 times as wide as the glabella, slightly upslop- 

 ing; palpebral lobes half as long as the glabella, elevated; distance 

 from posterior end of papebral lobe to posterior margin less than 

 length of palpebral lobe. Surface of test punctate. Length of cra- 

 nidium 4.8 mm. 



Remarks. — This form agrees with Onchocephalus in the shape of 

 the glabella and structure of the frontal area, but differs in the slightly 

 upsloping palpebral area and the greater length of the palpebral lobes. 

 In the last characters and general aspect the species approaches the 

 new genus Luxella. 



Occurrence. — Boulder B-ii, Bic; associated with Bonnia hrennus 

 (Walcott), Protypus sp. 



Disposition of material. — U.S.N. M. No. 123873. 



Genus CRASSIFIMBRA Lochman, 1947 



CRASSIFIMBRA, species undetermined No. i 



Plate 3, figure 23 



Available material. — One cranidium. 



Description. — Glabella of low convexity, with slightly concave side 

 outline, fairly truncated in front, showing four pairs of very shallow 

 furrows ; occipital ring not well preserved. Preglabellar field almost 

 vanishing medially; border of moderate width (sag.), with barely a 

 trace of a median rearward expansion. Palpebral area definitely 

 downsloping, slightly convex, half as wide as the glabella ; palpebral 

 lobes not preserved, apparently about one-third the glabellar length. 

 Posterior limbs slightly narrower (tr.) than occipital ring. Anterior 

 facial sutures slightly convergent from eye to marginal furrow ; pos- 

 terior branch as in typical species of Onchocephalus. Surface of test 

 finely granulated. Length of cranidium 4 mm. 



Remarks. — This species, intermediate in several features between 

 Onchocephalus and Crassifimbra, is referred to the latter genus on 

 account of the narrowness of the palpebral area. It differs from 

 Crassifimbra walcotti (Resser) in the greater relative length of the 

 glabella, deeper dorsal and marginal furrows, elevated and narrow 

 border, and granulated surface. 



Occurrence. — Boulder SS-i, St. Simon; associated with Protypus 

 reticulatus Rasetti. 



Disposition of material. — U.S.N.M. No. 123874. 



