LEOCPATES ATLANTICA. 131 



Chitinous teeth in mid-dorsal and mid-ventral lines. Feet sixteen in number, long and 

 prominent. The dorsal lobe has — just below the ridge of the foot — the basal segment of 

 the dorsal cirrus, the setigerous region in front being conical with a long black spine. 

 Dorsal bristles simple, stiff, tapering to hair-like tips. Shaft marked by transverse strise 

 almost to the tip, which has a regular series of minute spikes. Ventral division irregularly 

 conical with terminal papilla for spines; upper slope downward and outward, inferior 

 (more abrupt) downward and inward. The iridescent bristles form a dense tuft ; 

 shafts with close series of longitudinal and transverse strias, slightly dilated distally and 

 then bevelled — from the attachment of the terminal process to the point. Terminal blades 

 longest in upper third of tuft, shorter dorsally, shortest ventrally. Each is flattened, 

 slightly tapered and curved distally, where it is bifid — with a secondary process. The 

 bevelled edge of the blade is attached by a web to the shaft. Ventral cirrus long, slender, 

 subulate, and tapering — extending a little beyond the fleshy part of the foot. 



Synonyms. 



1896. Tyrrhena atlantica, Koule. Camp. 'Caudan/ Ann. Univ. Lyon, Aout-Septembre, 1895, p. 455, 



pis. xxi, xxiv, xxv, f . 9, 10, 24, 28 and 29. 

 1901. „ „ Mcintosh. Ann. Nat. Hist., ser. 7, vol. viii, p. 227, pi. i, f. 5, 6 and 8. 



Habitat. — Several specimens were dredged in the 'Porcupine' Expedition of 1870 

 at Station 9, on the Channel Slope, lat. 48° 6' N., long. 9° 18' W., in 539 fathoms, on a 

 bottom of grey mud. Bottom-temperature 48 o, Fahr., surface-temperature 64°*0 Fahr. 

 Off Ushant in 400 fathoms (J. E. Allen). 1 



In the ' Oaudan ' from a depth of 1410 metres in the Gulf of Gascony (Poule). 



Head (Plate LVIII, fig. 17) more or less quadrate, with the longer diameter antero- 

 posterior, and generally with a median depression and a somewhat cordate posterior 

 border, so that the eyes occur on an elevated ridge on each side. The anterior pair of 

 eyes are wide apart, large, rounded, and with a cuticular lens in the centre, the darkest 

 part of the pigment-ring, in spirit, being a crescent on the inner and posterior border. 

 The posterior pair are rounded or oblique in the preparations, the latter, in all probability, 

 being due to the presence of the pigment on the inner border. Both pairs lie in the 

 middle of the head. From the outer and inferior angle of the head on each side the palpi 

 project forward and downward, the segment at the tip being proportionally short, and 

 Claparede observes that, in his species, it can be partly invaginated. The organ is small 

 compared with that in the Syllids, is thickest at the base, and tapers towards the tip. The 

 tentacle, arising from the head internal and superior to the former, is subulate, much more 

 slender, and longer. In the median line between the posterior pair of eyes is a compara- 

 tively short, subulate, median tentacle, which is easily overlooked, especially in an 

 indifferent preparation. The edge of the proboscis projects in the preparations, and in 

 the median line dorsally is a prominent papilla, which lies under the anterior border of 

 the snout— fitting as it were between the palpi, and Claparede states that, in his form, it 

 is surrounded in life by a circle of cilia. In these preparations the eyes are considerably 

 1 I am indebted to Dr. Allen for this and other information on this species. 



