Iviii 
SYNOPSIS OF GENERA. 
Family, Rhinocarid^. 
Genus RHINOCARIS, nov. gen. 
Diagnosis. Cephalothorax univalvular, later¬ 
ally appressed; outline as in Ceratiocaris. An¬ 
terior extremity produced into a narrow, ver¬ 
tically flattened prora continuous with sub¬ 
stance of the carapace. The axial line of the carapace bears a low ridge along 
which it shows no inclination to separate when laterally compressed. Surface 
smooth or with one or more lateral carinae, and ornamented by finely elevated 
lines, granules or tubercles. Abdomen composed of not less than four smooth 
sub-cylindrical somites. Post-abdomen bearing three spines, of which the telson 
is elongate and conical and the cercopods flattened. 
This genus includes a series of forms which may tentatively be regarded as 
Phyllocarida, but which represent a type of crustacean structure hitherto unre¬ 
cognized, taxonomically intermediate between the univalve Phyllocarida, 
Hijmenocaris and Dictyocaris, and the Macrourous Decapoda. 
Family, Discinocarid^. 
Genus SPATHIOCARIS, Clarke. 1882. 
1882. iSpathioearis, Clarke. Amer. Juurn. Science. 
1883. Spathiocaris, Packard. Monog. North Amer. Phyllop. Crustacea. 
1883. Spathiocaris, Etheridge, Woodward and Jones. Kept. Committee Foss. Phyllop. 
1884. Spathiocaris, Cl.^^rkb. Neues Jahrb. fiir Min. 
1884. Spathiocaris, Dames. Neues Jahrb. fiir Min. 
1884. Spathiocaris, Von Koenen. Neues Jahrb. fiir Min. 
1884. Spathiocaris, Etheridge, Woodward and Jones. Second Kept. Committee Foss. Phyllop. 
1884. Spathiocaris, Jones and Woodward. Geol. Magazine. 
1885. Spathiocaris, Clarke. Devon. Faunas Ontario county. 
1885. Spathiocaris, Etheridge, Woodward and Jones. Third Kept. Committee Foss. Phyllop. 
1885. Spathiocaris, Dames. Neues Jahrb. fiir Min. 
1885. Spathiocaris, Zittel. Handb. d. Palseontologie. 
1886. Spathiocaris, Clarke. Geol. Succession in Ontario Co. 
Diagnosis. Carapace in one piece, elliptical, sub-conical and patelloid; apex 
situated at or near one focus of the ellipse. The cephalic cleft begins just in 
front of the apex and slowly widens to the anterior extremity. Surface orna¬ 
mented with closely set concentric lines and usually with fine radii on the ante¬ 
rior and posterior portions. 
