432 PROCEEDINGS OF THE ACADEMY OF [June, 



concave, and posterior straight. Eyes absent. Tentacles ver}- short, 

 the lateral shghtly the larger and about -j length of prostomium, both 

 pairs borne close together on the truncate lateral angles, directed 

 nearly straight forward, but slightly divergent. 



Parapodia short, especially anteriorly, the two rami widely separated, 

 least so in the middle region, where the branchife are highly devel- 

 oped. Xeuropodium and notopodium about equally developed 

 throughout, the former directed laterad, simple, truncate, conical; 

 with slight acicular lobe and circumsetal collar, but no distinct lamellae ; 

 cirrus very short, thick, conical, arising from ventral side of neuropo- 

 dium close to base. Notopodium directed somewhat oblicjuely dorsad, 

 also of simple, short, truncate, conical form, without lamellae; acicular 

 lobe well-marked and notched at end; circumsetal collar oblique, its 

 posterior portion high, the anterior very low. Xo dorsal cirrus, but 

 a special cirrus of short thick form on ventral side of notopodium, in 

 the branchiate segments closely connected with the external side of 

 the base of the branchial stem. 



Branchiae begin on V, as a minute process on the ventral and in- 

 ternal side of the cirrus ; this increases in size and develops dorsal and 

 ventral \vings, which assume the characteristic form by XV, though 

 continuing to increase in size for some segments beyond. In its typi- 

 cal development the branchia is extremely like N. phyllohranchia 

 Mcintosh, but the shape of the prostomium readily distinguishes the 

 two species; the branchia is a large WTinkled leaf-like structure, 

 through the middle of which runs a thick tapering midrib, the tip of 

 which projects slightly, and from which vessels pass into the expanded 

 portion. When best developed it occupies most of the space between 

 the two rami. Posterior to XXXV the branchiae undergo reduction 

 until the much shortened midrib alone remains, bearing a minute 

 process, probably the cirrus, on the dorsal side of its base. 



The setae are almost entirely destroyed, but their dark-colored bases 

 remain to indicate their arrangement. Anteriorly they are disposed 

 in both rami in rings around the acicula as centers, the posterior semi- 

 circle being composed of large, the anterior of small, setae Avhich soon 

 disappear, leaving only the posterior arc in parapodia farther caudad. 

 None of the setae are complete, but enough may be seen of those of 

 the anterior semicircle to show that they are camerated and very small 

 and delicate. Nothing whatever can be determined of the characters 

 of the posterior ones. A single slightly brownish, acutely pointed, 

 stout aciculum supports each ramus. 



Sagami Bay, 3,695, 175-190 fms. 



