198 PROCEEDINGS OF THE ACADEMY OF [Vol. LXXV 



A few fragments of tubes have the usual form and texture with 

 shells of Foraminifera. minute molluscan shells and fragments of 

 larger ones, sponge spicules, etc., attached to the surface. 



Stations 4310, off Point Loma Lighthouse, 71-75 fathoms, 

 green mud and fine gray sand; 4312, same locality, 95-135 fathoms, 

 fine gray sand and rocks; 4359, same locality, 98-220 fathoms, 

 green mud; 4420, off vSan Nicolas Island, 32-33 fathoms, fine 

 gray sand (8 specimens); 4421, same locality, 229-298 fathoms, 

 gray mud and rocks (2 specimens); 4431, off Santa Rosa Island, 

 38-41 fathoms, coarse gray sand, some mud, (3 specimens). Only 

 one specimen except as indicated. 



Polycirrus perplexus sp. nov. 



Prostomium a large flat or usually folded ovoid plate equaling 

 the first nine segments and half as wide as long, usually completely 

 concealed beneath the confused mass of tentacles. Tentacles so 

 numerous and tangled that Ijeyond the fact that they are attached 

 to the dorsum of the prostomium in several rows neither their 

 number nor arrangement can be made out. They are of various 

 lengths and degrees of contraction, some very slender, filiform 

 and terete, others short, broad and flat and more or less folded 

 or grooved. 



Peristomium a short ring bounding the mouth, with a short 

 rugous and tumid glandular lower lip or first ventral plate, and 

 expanded above into a triangular area bounded on the two sides 

 and anterior apex by the broad welt-like rim of the enveloping 

 prostomium. 



Somite II very short above where it is crowded between I and 

 III. Ventrally it is larger and bears the large ventral plate which 

 is divided into a quadrate anterior portion nearly continuous with 

 the first and a broad transversely elliptical posterior portion, both 

 of which are deeply furrowed longitudinally. Remaining anterior 

 thoracic segments about ^ as long as wide and more or less dis- 

 tinctly triannulate above and all setigerous. Ill bears a very 

 short, slightly developed ventral plate divided into a median and 

 paired lateral portions. Besides the three already mentioned, 

 there are nine pairs of large ventral plates and three or four pairs 

 of small ones of diminishing size, all divided bj^a deep narrow median 

 groove. When best developed the plates are nearly quadrate, 

 about twice as wide as long, thick, swollen and longitudinally 

 furrowed, so deeply on the largest specimens that they have the 

 aspect of being laminated. Posterior setigerous somites taper and 

 grade into the abdominal region. Here the body, exclusive of 

 the parapodia, is nearly terete. The segments are clearly defined, 

 somewhat rugous and terminate in a small conical pygidium. 



