No.4175.] MORTH-AMERICAN INVERTEBRATES. 731 
43. Lobes broad, not knobbed, all five well marked ; sete arising 
both from the summit of the lobes and from the intervening 
depressions. 8, F. campanulata Dobie (Fig. 7) 
d4. The two lateral iei very small, at first view bardly notice- 
able; dorsal lobe much larger than ventra 
ez. Corona ornamented with dots arranged in symmetrical pat- 
terns ; animal very small ; tube sometimes lackin 
9, F. algicola Hudson (Fig. 8) 
e2. Larger, corona not ornamented as ie er 
o, F. ambigua Hudson 
d5. The five lobes forming long slender iid arms, like those 
of Stephanoceros (Fig. 9 ents . I, F. millsii Kellicott 
c4. Lobes seven . 12, F. regalis Hudson 
a2. Setæ arranged in odi or ge io rows on the five long 
pointed lobes of the corona. . . . hi cos n eichhornii 
r. (Figs. 9 and to) 
B2. Corona without sete and apparently without d (a minute ciliary 
wreath can usually be detected on careful search) 
ar. Corona with one dorsal lobe, the coronal cup edged with a delicate 
festooned membrane ; body long, with a long slender tapering stalk, 
by which it is attached. Living in colonies of Méegalotrocha albo- 
flavicans . - . 14, Acyclus inguietus Leidy (Fig. 11) 
42. Coronal op a IS po HE. sack ; body short and thick ; no 
foot, — the animal being attached by a flat disk . . . . Apsilus 
ér. Coronal cup not oblique, its frontal margin horizontal 
15, A. vorax Leidy 
62. Coronal cup and its frontal margin oblique ; ganglion or brain in 
k 
the nec 
ez. Ventral margin of the coronal PY with a central convex lobe- 
like projection . . 16, A. bipera Foulke (Fig. 12) 
c2. Ventral margin of cup even, fh i central projecting lobe 
17, A. bucinedax Forbes (Fig. 13) 
B3. Corona without sete and not produced into long lobes, but with 
Strong conspicuous moving cilia forming a marginal continuous curve 
about the corona. In this curve there is a more or less conspicuous gap 
on the dorsal side. Mouth near the ventral side of the corona. On the 
body just below the corona either a single dorsal antenna, or two ventral 
ones, or all three, are noticeable. Trophi malleo-ramate (Fig. 16) 
ar. Individuals attached, separate, or in branching non-spherical colonies 
of few specimens (1-30 or thereabouts) 
^. Corona of four lobes (or in No. 21 of three lobes) ; ventral 
antennz obvious ; dorsal antenna minute Melicerta 
cI. Lobes of the corona when expanded wider than the tube; a 
Short, blunt chin on the ventral side below the corona; tube 
forme i Loe os S8, M. ripe 
d of nearly spherical pellets Seb (Figs. 14, r5, and 16) 
