v Annelida Ch^topoda of New Jersey. 121 



Dorsal setae, capillary ; those on the anterior segments (fig. 48) wider and 

 shorter than those further back (fig. 49) ; ten to fifteen in each fascicle in front, 

 gradually decreasing in number till only four or five are found on the posterior 

 segments ; they are arranged along the lateral line of the dorsum, and point up- 

 ward ; the ventral setae of the first six segments are similar to the dorsal, but 

 less numerous, and a little shorter ; back of the sixth segment the capillary setae 

 are nearly replaced by uncinate setae — a few, however, remaining in the lower 

 part of each series, even to the end ; the uncini (fig. 50) are arranged in a single, 

 transverse series, three to five in number, quite short, hardly projecting beyond 

 the surface ; they become gradually more numerous, each series having from 

 eight to twelve on the posterior segments, at the same time growing a little 

 longer ; they have four terminal teeth, the outer one being shortest (fig. 50), and 

 are covered by a delicate membrane. 



Anal segment with slightly thickened, rounded margin ; no appendages. 



Body slightly convex above, flattened below. 



Color : tentacles colorless ; branchiae dark green, with transverse bands of 

 light green or yellowish-green ; body colorless or light flesh-color ; a few speci- 

 mens with the first eight segments dark green. 



Length of adult, 6 nim ; with, 0.6 mm ; number of segments, 70. 



! Found in great numbers on beds of My tills edulis ; also in ditches to which 

 the tide-water had access, very near high-water mark ; the only other annelid 

 found under the same circumstances being Nereis limbata Ehlers ; the first 

 specimen taken was on a shell, dredged. This species lives in dirt tubes, which 

 they leave very readily when disturbed, and move about rapidly with quick, 

 jerking motions of the body; they soon settle to the bottom, and immediately 

 construct a new tube of any loose dirt that may be at hand. 



The first part of the generic name is intended to recall their peculiar method 

 of locomotion. The specific name is given in recognition of Mr. James E. Ben- 

 edict, a sound and enthusiastic naturalist — my associate for the past two years 

 in zoological work, who not only discovered the species in New Jersey, but has 

 since found it at South Nor walk, Conn. 



Female. 

 On one specimen the "middle third of the dorsum was covered by a very thin, 

 transparent, raised membrane. Unfortunately no figures of the young were 

 made, and the notes are not full. They were broadly rounded in front and be- 

 hind ; sides convex ; two small red eyes on the anterior margin of the head ; 

 lateral depressions indicating three segments ; two circles of cilia, one just back 

 of the head, the other near the posterior end. 



Fam. ARICIID^E. 



ANTHOSTOMA Schinarda. 



Neue Wirbellose Thiere, vol. i, part ii, p. 61. 1861. 



Anthostoma fragile Verrill. 



Verrill. Invert. Animals of Vineyard Sound, etc., p. 598. 1S74. 

 Webster. Annel. Chaet. of the Virginian Coast, p. 258. 1879. 



The branchiae may begin on any segment from the thirteenth to the twenty- 

 first, according to the size of the specimen. 

 Common in sand at low water. 



