[23] FAUNA OF OUTER BANKS, VINEYARD SOUND, ETC. 663 



A very siDgular Syllidian,* of which ouly the sexual forms are 

 known, was taken several times at the surface, in the evening. We 

 also took these in 1880 and 1881. They have probably been detached 

 from a verj' different stem-form. The genus is allied to ChcctosylUs Mgn., 

 but the head is entirely destitute of antennae. It has four large eyes 

 and swims very actively. 



OdontosylUs lucifera V., of both sexes, was very common in the sur- 

 face nets all through August and to September 15, but mainly in the 

 evening. With the latter a smaller and more delicate species usually 

 occurred, but in less abundance. This belongs to the genus Uusyllisj 

 and has been known to me for a number of years. 



* Teiraglene Griibe, 1863. — Sexual forms: Head distinct, with four large eyes, but 

 with no other appendages. Segments behind the head similar, all bearing large 

 parapodia, with long sette, a long dorsal cirrus, and a smaller slender ventral cirrus. 

 Caudal cirri two, long, submouilitbrm. 



Tetraglene agilis Verrill. — Trans. Conn. Acad., iv, pi. 25, Fig. 10. — Rather large 

 and stout, head broader than long, subtruncate, or even emarginate in front, con- 

 stricted abruptly behind ; eyes large with front lens round, the two pairs near to- 

 gether, the anterior a little larger and wider apart. Body-segments separated by 

 deep constrictions ; parapodia with large setigerous lobe, as long as the breadth of 

 the segments ; set* numerous, longer than the parapodia, the shorter ones with a 

 long, slender article ; capillary set* begin on the third segment ; cirri more or less 

 moniliform, slender, tapered, about four times as long as the breadth of the head ; 

 caudal cirri similar to dorsal; ventral cirri slender, smooth. Color of males, yellow- 

 ish white ; of females, pale orange yellow or salmon ; eyes brown; eggs reddish, laid 

 August 5, 1882. Length of largest ( $ ) about 25™" ; males about 20™°'. Taken in 

 the evening, at the surface, near Nomansland, September, 1880 ; Wood's Holl, August 

 4, 1881, and from August 5 to September 12, 1882. Description from life. 



t Eusyllis /enera Verrill, Trans. Conn. Acad., iv, pi. 13, Fig. 12, pi. 14, Figs. 4, a. h. — 

 Slender, 5™™ to 7™™ long, with very long, slender antennae and cirri, which are often 

 curled in spirals, and irregularly transversely constricted, smoothish in full extension. 

 Pharynx short, straight, with a large, sharp median tooth at the extreme anterior end; 

 the edge of the tube is divided into numerous (about 30) small, sharp denticles, be- 

 coming obsolete on the lower side; sheath of pharynx with a circle of larger, soft 

 papillae (about 13) in front of the tube. Stomach large, oblong ; intestine with a 

 pair of short, rounded, lateral pouches at the end of the stomach. The median an- 

 tenna and upper tentacular cirri are 3 to 6 times as long as the breadth of the body; 

 lateral antennae and lower tentacular cirri shorter ; the longest dorsal cirri are 5 to 6 

 times as long as breadth of body; shorter dorsal cirri alternate irregularly with the 

 long ones. The palpi are very flexible and changeable in form, prominent, flattened, 

 tapered or oblong, obtuse. Head rounded in front, widest in front of the middle, op- 

 posite the largest eyes. Eyes six ; four larger ones nearly equal, the anterior a little 

 larger and wider apart, near the sides of the head ; the minute frontal eyes are near 

 the inner bases of the antennae. Setae with an oblong, blade-shaped terminal article, 

 obtuse and slightly bidentate at tip. 



Sexual individuals have, also, fascicles of long capillary setae, beginning on the 

 fourteenth setigerous segment. 



Color translucent bluish white, pinkish or purplish-brown anteriorly, and more or 

 less purplish-brown or blue-gray on the sides of the body and more decidedly on the 

 bases of the parapodia; cirri white; pharynx and stomach pale brown; intestine 

 brown or olive-green, constricted between the segments; eggs showing through, pur- 

 plish-brown ; eyes dark red. 



New Haven to Vineyard Sound; frequent at surface in evening, at Wood's Holl, 



