732 
THE AMERICAN NATURALIST. [ VOL. XXXV. 
c2. Lobes when expanded of the same width as the tube; chin 
long and pointed ; tube of oP having the form of a pointed 
cylinder i 19, M. conifera Hudson (Fig. 17) 
£3. Lobes when DAAN more than three times the width of the 
body ; ventral antennæ very long ; tube gelatinous, without pel- 
lets : : . 20, M. tubicolaria Ehr. 
c4. Ures (ventral) pair at tikes dias: by a large notch; 
lower (dorsal) pair almost confluent, so that the corona seems to 
have but three lobes ; ventral antenna short ; chin two-pointed. 
Tube with ovoid fecal pellets, or floccose, without pellets 
21, M. janus Hudson (Fig. 18) 
62. Corona broad, of two lobes, with a wide dorsal gap; dorsal antenna 
minute ; ventral antennae obvious ; tube without pellets Limnias 
cz. Tube cylindrical, transparent, ringed by transverse ridges at 
regular intervals ; five horny processes on the dorsal surface of 
the body, below the corona 22, L. annulatus Bailey (Fig. 19) 
c2. Tube nearly cylindrical, not ringed, often partly covered with 
débris ; no horny processes on dorsal surface of the body ; ven- 
tral antennz very short . . . 23, L. ceratophylli Schrank 
¢?. Tube roughened with transverse rows of raised points; seven 
horny processes on the dorsal surface of the body below the 
corona; ventral antennz T equal in length to the diameter 
of the tube . 24, Z. shiawasseensis Kellicott 
63. Corona nearly ticdu dd x diid dorsal gap ; dorsal antenna 
very large, with two projections or hooks at its sides ; ventral 
antennæ small or absent . . . Cephalosiphon 
cI. Tube tapering to the foot, PREE EE with extrane- 
ous material ; foot very long and slender n . 25, C. D 
Ehr. (Fig. 20) 
c2. 
Tube irregular, semitransparent, uere per 
6g. Corona a wide oval (or nearly circular), indistinctly two-lobed ; 
dorsal gap minute, ventral antennz obvious ; dorsal antenna incon- 
pene or absent (Ecistes 
One or more dorsal hacks or ‘projections ‘eee ihe corona ; 
ventral antennz minute ; tube absent or small and irregular 
dr. Two dorsal hooks below the corona; — n 
branched into antler-like structures . . . 27 
es (Fi ig. i 
42. A single dorsal hook below the corona; foot very — 
animal without a tube, living in the mucilaginous matrix of t 
alga Gloiotricha pisum . . . 28, O. mucicola Kell 
c2. Antenne (ventral) very short ; no dew hooks 
T. ntennz set wide apart; tube very irregular an 
often beset with extraneous matter. . . 29, O. cry sia n 
Ehr. (Fig. 22) 
