376 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 64 



pair of strong postero-lateral furrows and three pairs of faint, short 

 furrows, the posterior two pairs of which extend obliquely inward 

 and backward, while the two anterior pairs extend inward and 

 slightly forward ; occipital ring smooth, rather strong and with a 

 well-defined occipital furrow separating it from the glabella. Fixed 

 cheeks of narrow to medium width ; postero- and antero-lateral limbs 

 broad ; palpebral lobes small. Free cheeks large, broad, and marked 

 by strong venation radiating from the base of the eye lobe outward to 

 the outer border. 



Thorax with eight segments ; axial lobe narrow, each segment 

 marked by a small, sharp median node situated on a slight forward- 

 arching fold of the surface near the posterior margin ; pleural lobes 

 wide and rather flat; pleural furrows strong; they extend across 

 from the anterior, inner side of the pleura to the outer posterior side. 



Pygidium large, with a distinct axial lobe divided into eight or more 

 rings that are continued out onto the broad pleural lobes as broad, 

 shallow furrows separated by narrow ridges ; the furrows terminate 

 just within a narrow border. 



Surface of exterior test marked by a very fine shallow pitting. 



Genotype. — Ogygia klotsi Rominger [1887, Proc. Acad. Nat. Sci. 

 Phil., p. 12, pi. I, fig. i]. 



Stratigraphic range. — Ogygopsis klotzi occurs in the Stephen 

 formation of the Middle Cambrian about 3,000 feet below the Upper 

 Cambrian and 2,000 feet above the Lower Cambrian. 



Geographic distribution. — This is a Cordilleran genus as far as 

 known. Ogygopsis klotzi occurs at Mount Stephen in eastern British 

 Columbia on the line of the Canadian Pacific Railway, also in the 

 Wasatch Range of northern Utah. 



Observations. — Ogygopsis recalls at once Ogygiocaris Angelin, as 

 represented by Ogygiocaris dilitata (Bfunn) and O. buchii (Brongni- 

 art). The most marked differences between the two genera are 

 in the presence of well-defined palpebral (ocular) ridges on the fixed 

 cheeks of Ogygopsis, and in general, the more primitive character of 

 the glabella and cephalon. 



The genus Orria differs from Ogygopsis in the almost entire ab- 

 sence of fixed cheeks, large palpebral lobes, very narrow postero- 

 lateral limbs, broad, straight pleural furrows and shorter axial lobe 

 of pygidium. 



Both Ogygopsis and Orria foreshadow in the Middle Cambrian 

 time the Lower Ordovician genera of the Ogygiocarinas, Ogygopsis 

 being nearer to Ogygiocaris than Orria. 



