1911.] NATURAL SCIENCES OF PHILADELPHIA. 277 



They closely resemble the tubes of Diopatra cwprea, but are scarcely 

 more than one-half their diameter. 



Stations 4,457 (tubes only), off Point Pinos Lighthouse, Monterey 

 Bay, 40-46 fathoms, dark green mud ; 4,467, off Santa Cruz Lighthouse, 

 51-54 fathoms, soft dark green mud; 4,519, off Point Pinos Light- 

 house, 27-35 fathoms, hard gray sand (type). ■ 

 Hyalinoecia juvenalis sp. nov. PI XVIII, figs. 86-95. 



A small species represented by the anterior ends of two individuals, 

 which, though mature, retain certain characters of setae, etc., which are 

 found in quite young examples only of H. tubicola. The cotype, 

 comprising the head and 35 segments, is 19 mm. long and 1.9 mm. in 

 maximum width. The type, of the same size, has 32 segments and a 

 posterior regenerating cone. 



Prostomium trapezoidal, the greatest width posterior and about 

 one- third more than the length, the anterior and posterior sides convex, 

 the converging lateral sides nearly straight. Frontal tentacles small, 

 less than one- third length of prostomium, situated at antero-lateral 

 angles, directed somewhat ventrad, but little divergent, subfusiform, 

 about twice as long as thick, the pedicles much constricted. Median 

 and posterior lateral tentacles situated well within posterior half of 

 prostomium close together on dorsal face; anterior lateral tentacles 

 farther forward on lateral margin. Ceratophores of anterior paired 

 tentacles about as long as thick and 4-annulate, styles thickish and 

 stout, barely reaching III. Ceratophores of median and posterior 

 paired tentacles very short, obscurely divided into three annuli, the 

 styles smooth, moderately slender, about one-half the diameter of the 

 anterior pair, tapered, the median reaching to IX, the longest lateral 

 to XL Eyes black, very conspicuous, immediately behind the ante- 

 rior and below the posterior paired tentacles. The type has but one 

 pair about one-half the diameter of the base of the anterior tentacles ; 

 the cotype bears a second pair, almost as conspicuous and immediately 

 dorsal to the first pair. Palps rather small, about one-third width of 

 prostomium, globoid, directed ventrad immediately in front of mouth 

 and only slightly in contact medially. 



Peristomium small, scarcely wider than prostomium and less than 

 one-half as long, bearing the bilobed posterior lip. Somite II very 

 much larger, nearly twice as wide and three times as long as the 

 peristomium, extending forward and embracing the sides of the latter. 

 The next few segments diminish in length rapidly until the normal 

 length to width ratio of one to four or five is reached at somite VI. 

 Beyond this point the segments continue to increase in size and the 



