DISCI NOCARID^. 
SPATHIOCARIS, Clarke. 1882. 
Spathiocaris Embrsoni. 
PLATE XXXV, FIGS. 12-lS. 
Spathiocaris Einm-sonii, Clakke. Amer. Jour. Science, Third Series, vol. xxiii, p. 477, pi. 0, fig's. 1-3. 1882. 
Spathiocaris Emo’sonii, Packard. Monog. N. Amer. Phyllopod Crustacea. Twelfth Ann. Kept. U. S. Geol. 
Surv., p. 451. 1883. 
Spathiocaris Etnersoni, Clarke. Neues Jahrb. fur Min., etc., p. 180. 1884. 
Spathiocaris Emersonii, Etheridge, Woodward and Jones. Second Rept. Committee on Fossil Phyllopoda 
of the PaliEOzoic Rocks, p. 7. 1884. 
Spathiocaris Emersonii, Jones and Woodward. Geol. Mag., Dec. hi, vol. i, p. 348. 1884. 
Spathiocaris Emersoni, Clarke. Bull. U. S. Geol. Surv., No. 16. Higher Devonian Faunas, Ontario county, 
N. Y., p. 46. 1885. 
Spathiocaris Emersonii, Etheridge, Woodward and Jones. Third Rept. Committee on Fossil Phyllopoda 
of the PaliEOzoic Rocks, p. 3. 1885. 
Carapace ovate or elliptical in outline; surfixce elevated and sub-conical, some¬ 
what flattened on the posterior slope, more abruptly depressed at the sides. 
The apex is situated somewhat anteriorly and connected by a low ridge with 
the inner angle of the cephalic cleft. Tliis cephalic or rostral cleft takes its 
origin just in front of the apex of the shield and in uncompressed specimens 
widens slowly outward. In flattened individuals the inner angle and the 
width of this cleft are exaggerated. The surface of the shield is marked 
by regular, continuous, closely appressed concentric ridges, following the 
outline of the margin, becoming somewhat broader on the extremities and 
crowded on the lateral portions. At the posterior extremity the surface 
is cancellated by abundant radii, and similar radiating lines are visible in 
the anterior region along the margins of the cephalic notch. The outline of 
the carapace appears to vary with advancing growth, in mature individuals 
being nearly elliptical, but in younger specimens appearing broader at the 
