PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 171 



emarginate at the tip, with a distinct sutural line along the middle above. 

 Tentacular cirri small, papilliform. Parapodia small, each with a suiall 

 dorsal and ventral cirrus and a large, obtuse, setigerons lobe. Sette of 

 several kinds, the usual arrangement being as follows : one or two aci- 

 cula shorter than the other sette, tapering, straight, spine-like, one usu- 

 ally acute and the other blunt at tip ; one longer, slender, simple seta, 

 curved and slightly enlarged toward the end, which suddeuly narrows 

 to a small ;icute tip; one, or sometimes two, of similar size and length, 

 straight and abruptly expanded or spatulate near the end of the shaft, 

 and bearing a long, very slender, acute, terminal piece ; two or three 

 unequal com])ound setie, with the shaft spatulate at the end and bearing a 

 short, acute-triangular, terminal i^iece. Posteriorly the lowest is a sim- 

 ple, curved seta, with a short, sharp tip, similar to the upper one, but 

 shor ter, more tapered, and less curved. The pharynx occui)ies about four 

 segments ; the median tooth is rather large. Stomach large, occupying 

 two segments, oblong, with many circles of granules. Caudal cirri re- 

 latively large, elongated, enlarged in the middle, tapering to acute tips, 

 their length greater than the diameter of the body, much longer than the 

 median antenna. Color, pale salmon. Length, 5'"'" to 7""". 



Thimble Islands and Savin Eock, near iSTew Haven, Conn., '2 fathoms, 

 among algae, and at low-water, among the debris attached to tubes of 

 Biopatra, October, 1873, and October 15, 1875 (A. E. Verrill). 



A specimen, probably a sexual form of this species or P. duimr^ was 

 taken in Vineyard Souiul, at surface, July 10, 1875. It was similar an- 

 teriorly, but on the segments behind the 11th there were fascicles of 

 long, slender setse, twice as long as the diameter of the body. Color, yel- 

 lowish green. 



Nereis alacris, sp. uov. 



Body rather slender, slightly enlarged behind the buccal segment. 

 Antennae slender and pointed. First pair of superior tentacular cirri 

 very long and slender, about equal to the first six segments ; those of the 

 second pair more than one-third longer, reaching about to the tenth seg- 

 ment; ventral cirri also long and slender, about one-third as long a;; the 

 corresponding superior ones. Caudal cirri remarkably long and slender, 

 longer and more slender than the longest tentacular cirri. General color 

 of head and anterior segments bright olive-green ; posterior segments 

 and appendages tinged with orange-red ; bases of antennae and cim 

 tinged with purplish red; anterior eyes dark green with a red center, 

 posterior pale red with a dark red center; ndddle of head pale green ; a 

 row of more or less connected and sometimes confluent light spots 

 extends along the back, one to each segment ; these spots are usually 

 greenish white anteriorly, yellowish posteriorly. Smaller specimens are 

 plainer colored, mostly greenish or brownish, often without dorsal spots. 



Parapodia, in the middle region, of moderate size ; upper rami longest, 

 having an inferior and superioT branchial lobe, or lingula, of about e(jual 



