50 IOWA STUDIES IN NATURAL HISTORY 
floored the tide-pool. They appeared to be similar in structure, 
but after close study several genera were found among them. 
Localities: Jamaica; Barbados; Dry Tortugas; Ponce, Bo- 
queron Bay, reef at Ponce, Mayaguez, Guanica Bay and 
Hueares. 
Dasychone conspersa Ehlers 
Plate VII, Figs. 1, 2, and 6 
This beautiful little Sabellid could be seen under the water 
only at low-tide. Being very sensitive to stimuli, it would with- 
draw quickly into the tube upon being disturbed. The body is 
fuscous brown, irregularly sprinkled with dark spots. At the 
base the branchiw are a reddish brown, shading to yellow at 
the tips. The branchial filaments are alternately crossed at 
irregular intervals by red and brown bands. The branchie are 
bilobed. They are situated on a short basal lamina, each bear- 
ing 19 filaments nearly equal in size except two smaller ventral 
ones. Each filament is closely pinnated. A short portion of 
the apex of each rachis is free from pinnules. On the back or 
outward aspect of the rachis there are two sets of sense organs 
in pairs and alternating with each other: (1) the black eye- 
spots; (2) the smooth whitish filaments, probably tactile in 
function. 
The body, including the branchie, is 26 mm. in length. The 
greatest width, which is at the third segment, is 3.5 mm. The 
body narrows anteriorly, and posteriorly it decreases to almost 
2.5 mm., but widens a little before coming to a blunt end. There 
are 87 segments. In general the body is flattened except in the 
thoracic region, where it is strongly arched dorsally and flat 
ventrally. There are 4 buccal tentacles: 2 short triangular 
dorsal ones and 2 narrow elongated ventral ones. The buceal 
segment is short and is fortified by a small bundle of sete and 
a ventral shield. The collar is low and in 2 lobes, gaping wide 
dorsally and meeting ventrally. The lobes are slightly elongat- 
ed and triangular. On the ventral side in the posterior region 
there is an elongated trough-like depression, extending through 
about 20 segments. In the bottom of this depression lies the 
ventral groove, which extends forward to about the ninth seg- 
