748 THE AMERICAN NATURALIST. [Vor. XXXV. 
covered with areolations. Anterior dorsal margin of the lorica 
truncate, without points 150, P. ¢runcatum Levander (Fig. 107) 
Lorica soft, covered with coarse areolations, partly arranged 
in very irregular rows ; hinder part of the body retractile and 
extensile ; when extended the body ends posteriorly in a blunt 
Dant uos e eoo 151, P. molle Kellicott 
dg. Lorica soft, covered with coarse irregular cuticular vesicles ; 
body thick, short, rounded behind 
152, P. hudsoni Imhof (Fig. 108) 
c4. Foot projecting from the ventral surface, small, lightly ringed, 
and ending in a single pointed toe. Lorica compressed later- 
ally so as to be nearly circular in side view, with a sort of 
projecting collar for the protrusion of the head; in dorsal or 
ventral view oblong. Lorica rose color; internal organs blue, 
green, and orange . 153, Gastropus stylifer Imhof (Fig. 109) 
£5. Foot very small and ending in two small toes ; lorica thin, 
compressed laterally, flask-shaped, with the foot projecting from 
the ventral surface ; size about .10 mm. 
154, Gastropus minor Rousselet 
(See also No. 223, Cochleare turbo) 
62. Foot present, not transversely wrinkled nor ringed (though often 
jointed 
cr. Foot distinctly jointed and ending in two small toes; lorica 
with an arched dorsal plate and a nearly flat ventral one ; dorsal 
surface tuberculate or faceted but not bearing spines. Spines 
present at the anterior and posterior margins of the lorica 
dr. Lorica with ten spines in front and four behind, its whole 
form markedly unsymmetrical ; surface faceted and covered 
with raised points . . . . 155, Brachionus militaris Ehr. 
d2. Lorica flattened, only slightly arched dorsally ; dorsal sur- 
face faceted and roughened ; two spines in front, turned 
ventrally at their tips ; two posterior lateral spines. Wo ye 
156, JVoteus quadricornis Ehr. (Fig. 110) 
c2. Lorica flattened and bearing one or more spines on its dorsal 
surface (spines at the posterior margin of the lorica may or may 
not be present also). Foot distinct, jointed, ending in one or two 
toes 
dr. Spines on the dorsal surface of the lorica eight or twelve 
(including four at the posterior margin); lorica subquadrate 
rough, toothed at the edges; head covered by a chitinous 
£dd Xo s cocum c PNE 
ez. Eight spines on the dorsal surface of the lorica 
Jt. Foot bearing two large dorsal spines or spurs 
157, P. collinsii Gosse 
fe. Foot without dorsal spines . . 158, P. serica Thorpe 
