112 THE AMERICAN MONTHLY [May 
Tesselated cruciformly, facets 6. Marine.....cruciformis Q.1895,125 
Not tesselated; middle spines sickle-shaped............ falculata. Sup 
Lorica ridged, tesselated, spoon-shaped; spine straight..cochlearis 
Lorica ridged, tesselated,oblong oo. oe eee cece cece schista. Sup 
Lor. not rgd, tesselated, subquadrate or triangular. Stipitata. Sup 
Posterior spines equal, (g) 
Posterior spines, unequal, (h) 
Lorica quadrate ; hind spi. short, frontal straight...testudo. Sup 
Lorica obl.-square ; ridges serrate; hind spines short.....serrulata 
Lorica oblong-square ; ridges not serrate; hind spi. long..aculeata 
Ventrum deep curved ; tesselated. Ascension Isl....procuryva. J.,’91 
Ventrum flat; anteriorly rough; dorsum tesselated........ valga. Sup 
Ventrum do.; sm’th, faintly tesselate. Brisbane..scutata J.’91, 305 
Movable oar-shap’d process each side; sm’th. Marine. biremis. Sup 
No movable process; tesselated. Aquatic............ quadridentata. Sup 
63. NoTHoLca. II., 125. Sup. 56. 
eer er sre ngngmhroeenanm 
A Fresh water, (a) 
A Marine, (e) 
a Posterior spine present, (b) 
a Posterior prolongation truncate, (c) 
a Posterior border rounded, (d) 
b Two frontal spines unequal, 1 long, curved; hind spine 
NReE LOMA ica sc andedlcy Gan canenbtapupdesatacAaend) ereeciala een longispina 
b Frontal spines sub-equal; lor. longitudinally ridg’d... foliacea. Sup 
b Frontal spines sub-equal; lorica wavy-striate............ heptodon. Sup 
c Prolongation long, tapering ; ventrum concave ........... acuminata 
c Prolongation short, broad, not tapering... labis. Sup 
d Lor. elongated, dorsum with 12 longitudinal striz....... striata. Sup 
d Lorica dehouias ibamceadest no strie; ventral sides sloping: 
Pn Es C1 BST a .polygona. Sup 
Posterior prolongation truncate, (f) 
Posterior prolongation rounded, (g) 
Ridges reaching hind margin; lateral spines dorsal 
PREV RUG eR MRR ART EMOR A EN NTE hoodii. Q., 1893, 158. 
Ridges reaching hind margin; lateral spines none........ thalassia 
Ridges not reaching hind margin; lat.spines present.jugosa. Sup 
Ridges not reaching hind margin; lateral spines none.......... scapha 
Dorsum with 12 longitudinal striz........ striata. Sup 
Dorsum not striated; lorica rhomboidal, front truncate. 
das rhomboidea. Sup 
g Dorsum not striated; 2 movable lateral spines.......spinifera. Sup 
64. ERETmMIA. ILI., 128. 
hh Oo O 
0Q OQ Hh Hh Fh 
Setz 6; 1 dorsal, 1 ventral, 4 terminal... eee cubeutes 
Setze 5; 1 dorsal, 2\on- each sides) it pentathrix 
Sete 4; 3 frontal, 1 postero-terminal. Aquatic......0000000000..... tetrathrix 
Sete 3; 2 frontal, 1 postero-terminal. Aquatic... trithrix 
