52 Annelida CTwetopoda 
laterally, flattened above ; the posterior third is thin, 
flattened both above and below. 
Color : first third white ; middle third brown, semi- 
transparent ; last third white ; or the anterior third may 
be light flesh color, posterior two-thirds yellowish ; bran- 
chiae red. 
Found occupying tortuous galleries in compact bivalve 
shells. In some respects this form agrees with P. hoplura 
Clpd., but is not identical with it. 
POLYDORA C^CA 71. Sp. 
PLATE IX, FIGS. 119-122. 
Head emarginate in front; lateral lobes bluntly rounded, 
short, no eyes. A rounded carination extends from the 
head to the anterior margin of the 4th segment. 
Tentacles, mere threads ; in extension from 10 to 12°"° 
long, white, canaliculated ; margins of channel flake- white, 
interrupted by thirteen transverse dark purple lines, which 
reach about half-way around the tentacles. Length of 
markings to spaces included between them about as 1 to 3. 
First segment with dorsal ramus only; ramus small 
and with shorter setse than those of the following segments. 
Second, third and fourth segments with short, blunt, 
finger-shaped dorsal and ventral cirri. 
Branchiae begin on 7th segment, are of the ordinary 
form, but very numerous, existing on over 100 segments. 
The last three are very short, and are followed by sixteen 
segments without branchiae. 
Terminal sucker funnel-shaped, interrupted below ; anal 
opening with crenulated margin. 
Setae. Very numerous in anterior dorsal rami; some 
very long, at least one-half longer than the branchiae. 
These long setae for the most part have the form shown in 
f. 119, but some are narrower. In the upper part of the 
bundle are shorter setae (f. 120). 
