JOHNSON: POLYCHAETA OF PUGET SOUND REGION. 413 
branchiae and dorsal cirri. Dorsal and ventral setae in small fas¬ 
cicles. Ventral ramus of foot continued ventrad as a leaf-like ex¬ 
pansion, but not extending below the medio-lateral line. Anus 
on dorsal side of pygidium; anal cirri long and slender. 
Length , 19*2 mm.; width of thorax, 3 mm.; width of abdomen 
(including parapodia), 2 mm. 
This species burrows in sandy shores, near low-water mark, 
whereas the much commoner and more widely distributed species of 
Aricia found on the Californian coast has its habitat among the 
rhizomes of Phyllospadix. The present species is represented in 
the material from Puget Sound by a number of incomplete speci¬ 
mens collected by the Columbia University Expedition and by Miss 
Robertson. 
Levinseniidae. 
Aricideopsis gen. nov. 
Characters of Aricidea Benedict and Webster, but differs from 
it in having well-developed parapodia and setae on the peristomium, 
and no ventral cirri. Eyes very large, compound. Anal cirri, two. 
29. Aricideopsis megalops sp. nov. PI. 10, figs. Ill, 112. 
PI. .11, figs. 113, 114. 
Form of moderate length, gradually tapering from the anterior 
to the posterior extremity, color of preserved specimen pale yellow, 
the dark intestine showing through in the posterior portion. Para¬ 
podia with distinct rami flattened into foliaeeous expansions, much 
the largest dorsally, and in the anterior half of the body; setae in 
both rami; uncini and capillary setae in all ventral rami (except 
the last two or three, which are achaetous) back of the 18th. 
Frostomium (Fig. Ill), the full breadth of trunk, rounded ante¬ 
riorly, elevated in a median thickening at base, which is bilobed 
anteriorly, and bears the median cirrus and the large crescentic 
eyes. 
Parapodia (Figs. 112, 113) with dorsal rami expanded into leaf¬ 
like form on somites 2-24 and beyond, gradually becoming smaller 
and more rounded ; towards end of series the upper lobe becomes 
minute; ventral lobe rounded, always smaller than the dorsal; a 
filiform gill ( br .) on somites 2-27, often with lanceolate tip. Setae 
(Figs. 112,113, 114) of two sorts : capillary and “ hooded crotchets ” ; 
both kinds occur in the ventral rami back of the 17th somite; at 
