320 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [614] 



posterior fold. Tentacles very numerous, crowded, long, and slender. 

 Branchiae four, rather small ; those of the anterior pair somewhat the 

 larger ; those of both pairs are repeatedly dichotomously divided from 

 close to the base. The divisions are short and not very numerous, and 

 diverge at a wide angle. Fifteen segments bear small fascicles of slender 

 setae, commencing at the next behind the last brauchiferous segment. 

 The third and fourth setigerous segments of the male bear small, slender 

 lateral cirri. Ventral shields about thirteen ; the first six transversely 

 oblong, and nearly equal in width ; the last seven narrowing rapidly 

 to the last, which is acutely triangular. Color, when living, light red, 

 or flesh-color. 



Length, 35 mm ; diameter, 3 mm to 4 mm . 



New Haven to Vineyard Sound, from low- water to 6 fathoms; off 

 Watch Hill, 4 to 6 fathoms, in tubes composed of bits of shells and grains 

 of sand, attached to Laminaricv. 



SCIONOPSIS Verrill, gen. uov. 



Body composed of numerous segments, of which 17, following the 

 third, bear fascicles of slender setas, and the following ones have only 

 small uncigerous lobes ; second and third segments bear branchiae, 

 and have their anterior margins prolonged into membranous, collar-like 

 expansions; that of the second forming broad, lateral lobes behind the 

 tentacles ; that of the third forming behind the branchiae a dorsal col 

 lar or sheath, beneath which they can be retracted. Branchiae typically 

 four. Those of the first pair usually larger, but generally one or more 

 are absent, and frequently the anterior ones are smallest, or those of the 

 same pair may be unequal, owing probably to the facility with which 

 they may break off and be reproduced ; they are palmately branched 

 and supported on elongated pedicels. Tentacles numerous and crowded. 



This genus is allied more closely to Pista than to any other yet de 

 scribed, but differs in the structure of the branchiae and character of 

 the collar formed by the third segment. 



SCIONOPSIS PALMATA Verrill, sp. nov. (p. 321.) 



Body elongated ; rather slender ; thickened but not distinctly swollen 

 anteriorly, tapering gradually to the posterior end. The setigerous feet 

 commence at the fourth segment, or next behind the branchial collar, 

 and are all quite prominent, the first three or four being a little smaller 

 than the rest ; the setae are rather long. The uncigerous feet commence 

 on the second setigerous segment. Behind the last setigerous segment 

 the uncigerous feet are smaller, somewhat prominent, and extend to the 

 anal segment. Ventral shields about 20 ; the most anterior ones are trans 

 versely oblong ; the succeeding ones squarish, gradually tapering to the 

 last, which are very narrow. Anal segment tapering ; its orifice with 

 a crenulated margin. Branchias large, with numerous palmate divisions 



