322 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [616] 



much narrower and more prominent ; anteriorly they are very broad. 

 Ventral plates rather broad anteriorly, those posterior to the seventh 

 or eighth suddenly narrowed. Branchiae in three pairs, small, finely 

 arborescently divided, the divisions numerous ; posterior pair consider 

 ably smaller than the others. Cephalic lobe with a somewhat prolonged 

 frontal border, broadly rounded in front, with an entire margin. Color 

 bright red ; tentacles flesh-color. 



Length, 50 mm or more ; diameter, 2.5 mm to 3 mm . 



Vineyard Sound; Wood s Hole on piles of wharves just below low- 

 water mark. 



POLYCIRRUS EXIMITJS Verrill. Plate XVI, fig. 85. (p. 320). 



Torquea eximia Leiily, op. cit, p. 14 (146), Plate 11, figs. 51, 52 (setae), 1855. 



In this species there are twenty-five setigerous segments, bearing 

 small fascicles of long, slender setre ; about seventy posterior segments 

 bear uncini only ; anteriorly the uncini commence on the eighth setig 

 erous segment. There are nine ventral shields, divided by a median 

 ventral sulcus. The frontal lobe of the head is large, elongated oval 

 or elliptical. The posterior lobe of the mouth is large, rounded. Body 

 and tentacles bright blood-red ; the body is often more or less yellowish 

 posteriorly. 



Great Egg Harbor to New Haven and Vineyard Sound ; low-water 

 to 10 fathoms. 



A species of this genus was also dredged in 19 fathoms off Gay 

 Head, but its identity with the above is uncertain. Another species, 

 remarkable for its brilliant blue phosphorescence, is common in the 

 Bay of Fundy. The P. eximius does not appear to be phosphorescent. 



CH^TOBRANCHUS Verrill, genus nov. 



Allied to Polyclrrus and, like the latter, destitute of blood-vessels. 

 Body much elongated, composed of very numerous segments, nearly 

 all of which bear fascicles of setse. Segments of the middle region bear 

 simple, or more or less branched, branchial cirri, each of their divisions 

 tipped with slender seta3; these cirri are wanting on the anterior and 

 posterior segments, the first and last ones being smaller and more simple 

 than the rest. The cephalic segment expands into a broad, tentacular 

 or frontal lobe, which is rounded or emarginate anteriorly, and often 

 more or less scolloped laterally. Tentacles crowded, very numerous, 

 long and slender in extension, capable of being distended by the blood, 

 as in Polycirrus, &c. 



CH^ETOBRANCHUS SANGUINEUS Verrill, sp. nov. (p. 320.) 



Body greatly elongated, much attenuated posteriorly, more or less- 

 swollen anteriorly, but narrowed toward the head, the thickest portion 

 being usually between the tenth and fifteenth segments. The branchial 

 cirri commence at about the ninth segment, those of the first pair being 

 short, simple cirri; those on the next segment are once forked ; those on 



