68 Annelida Choetopoda 
PHRONIA n. gen. 
Head divided into palpi. Body elongate, flattened, 
composed of numerous segments. First segment with two 
pairs of tentacular cirri, without setse. Dorsal cirri of 
second segment similar to the upper tentacular cirri. 
Remaining dorsal cirri flattened, thin. Feet uniramous. 
Setse all simple, capillary. Anal segment not seen. 
Phronia tardigrada n. sp. 
PLATE Xl« FIGS. 158-163. 
Head (f. 158), width greater than length ; lateral margins 
slightly concave ; posterior margin straight to the middle 
third, then curving suddenly backward, encroaching on 
the front of the buccal segment ; on the lower surface, close 
to the inner anterior margin of the frontal lobes (palpi), 
two minute papillae, which, pointing forward and inward, 
project a little beyond the palpi; in front the division be- 
tween the palpi extends about one-third of the way back; 
above, is continued as a shallow depression ; below, as a 
deeply impressed line, to the posterior margin : palpi 
broadly rounded in front. Antennas two, conical, lateral, 
very small. 
Tentacular cirri ; superior, conical, elongate, turned for- 
ward, reaching a little beyond the head : inferior, conical, 
minute. Sides of the buccal segment turned forward, 
embracing the head. The mouth has a crenulated posterior 
margin. Dorsal cirri of the second segment similar to 
those of the first, but a little longer and very slightly flat- 
tened ; after the first they have a cylindrical or slightly 
tapering basal article; back of the second segment they 
are suddenly shortened and flattened, becoming leaf-shaped 
(figs. 159, 160). The substance of these cirri is crowded 
with small glandular bodies, and those of the anterior seg- 
ments have a series of minute cylindrical papillae along 
