304 
THE YOYAGE OF H.M.S. CHALLENGER 
cirrus, whicli projects outwards as far as tlie tip of the former regiou. A little 
within the margin of the latter is a blood-vessel, large below but diminishing dorsalty. 
The setigerous lobe bears two long brownish sj^ines. Superiorly the simple bristles 
show no evident wing, though slightly dilated beyond the shaft. They taper to a fine 
point. The brush-shaped bristles accompanying them have rather wide tips. The shafts 
of the compound bristles (PI. XXa. fig. 26) present a distinct curve below the dilatation. 
The terminal piece is long, and the guard or wing is bevelled at the tip, for the loAver 
process of the fork comes off nearly at a right angle. 
At the twentieth foot (PI. XXXIX. fig. 22) the two spines of the setigerous region 
have become blackish, and inferiorly a bro^vnish -black bifid hook appears. The chief 
fang of the latter is long, and the distal process is also well marked. The ventral cirrus 
forms a broad and somewhat triangular lobe. 
A noteworthy feature in transverse sections of this form is the great size of the 
ovoid ventral longitudinal muscles, which surpass the dorsal in bulk. When sections 
are made through the nerve-cords in the line of the ganglia the area is large and 
rounded, and an indistinct canal exists superiorly, though some doubt still remains on 
this point. In certain very thin sections two small canals are present, but only one is 
well defined. The edges of the ventral longitudinal muscles almost touch in the middle 
line, being separated by the narrow pedicle of the nerve-area. In the general character 
of such sections this form approaches the Onuphididse. 
The Eunicidse characterised by a very limited distribution of the branchige are 
Eunice hellii, Aud. and Ed., which is occasionally found on our own shores, and 
Eunice stragulum, Grube, from the Philippines. Kinberg likewise constituted the 
genus Nausicaa,'^ for a species devoid of tentacular cirri, and in which the short simple 
(cirrus-like) branchiae were confined to the segments seven to eleven. It was found at 
St. Jose, near Panama. 
Family Onitphidid^. 
The Onuphididse are fairly represented in the collection, eleven species referable to 
the genus Nothria being present, and several others, included under the genera 
Hyalincecia and Onupliis. This contrasts very favourably with previous Expeditions. 
Thus four are described ’ by Kinberg in the voyage of the frigate “Eugenie.” This 
author has no example of Nothria, but the representatives of the genus Diopatra are 
numerous, the reverse being the case in the collection of the Challenger.' The Philip- 
pine collection of Grube produced only a single member of the group, and only two 
occur in that of the exploring ship “ Gazelle.” None are given by Schmarda, and only 
1 Ofversigt Ic. Vetensk.-Akad. Forliandl., 1864, No. 10, p. 565. 
