Mr. P. II. Gosse on new or little-knoivu Marine Animals. 309 



able, each with a fiUforni cirrus above, a pencil of short bristles, 

 and a second pencil of long straight convergent bristles. 



C thalassina (mihi). PI. VIII. fig. 5. 



Length ^th of an inch ; colour of some specimens a lively pel- 

 lucid sea-green, of others pale orange or fawn-brown : all the 

 members colourless. 



The head is distinct, with two large conspicuous eyes, of a 

 very dark red hue. The front of the head, which is slightly 

 two-lobed, bears a pair of porrected antenna?, the basal portions 

 of which are large and bulb-like, giving rise to two diverging 

 filaments, of which the interior is the shorter, and is often much 

 convoluted. Between these antennge and the eyes are two 

 minute horn-like processes, which may perhaps be considered a 

 supplementary pair of antenna?, in which case the total number 

 is seven. Immediately behind the eyes are three large antenna? 

 (two lateral and one medial), which taper to a blunt point, and 

 are more than half as long as the body ; they are directed back- 

 wards, and are generally more or less curled and convoluted. A 

 tentacular cirrus springs from the base of each lateral antenna. 



Segments twenty-tive, exclusive of the head. Each is fur- 

 nished with a pair of feet, of which the first three are smaller 

 than the rest, and stand out transversely. All the rest point 

 backwards (but are very free and mobile), and are of a long-oval 

 shape, diminishing regularly to the tail. Both these and the 

 anterior series carry a superior cirrus, which is filiform, wrinkled, 

 but not moniliform, and a little longer than the foot itself. 

 Both series have also a pencil of short bristles, and the posterior 

 series have in addition a second pencil, which is straight, con- 

 vergent, twice as long as the foot, and directed obliquely back- 

 wards. The ovate feet in regular distichous arrangement, with 

 these long pencils, have a very striking resemblance to an ear of 

 barley with its grains and awns ; a resemblance which 1 have 

 commemorated in the generic appellation, from Kptdi], barley, 

 and eZ5o9, likeness. The ultimate and penultimate segments are 

 minute, and are destitute of cirri and bristles. 



Some half-dozen of these little worms were dipped from the 

 surface of the Bristol Channel near Ilfracombe, on a calm after- 

 noon in August last. They swam with excessive agility by a 

 rapid horizontal undulation of the body, in which the long pen- 

 cils reflected prismatic rays. The moment this undulatory move- 

 ment ceased, they usually bent themselves into a crescent or 

 circle. 



The genus reminds one of loida of the late Dr. Johnston, but 

 is widely remote from it ; the bifid antenntc are very peculiar. 



