228 
THE VOYAGE OF H.M.S. CHALI.ENGEK, 
Nereis jpatagonica, n. sp, (PI. XXXV. figs. 13, 14, 15; PI. XVIIa. figs. 1, 2). 
Hahitat. — Trawled at Station 313 (at the eastern end of the Strait of Magellan), 
January 20, 1876; lat 52° 20' S., long. 67° 39' W.; depth, 55 fathoms; bottom 
temperature 47°’8, surface temperature 48°‘2 ; sea-bottom, sand. 
Head rather longer than broad, with two conspicuous pigment-belts running backward 
from the bases of the tentacles. The latter about two-thirds the length of the head. 
Palpi large, tentacular cirri of moderate length, the longest extending to the eighth foot 
in a young specimen. Paragnathi — I. and II. absent ; III. a single small tooth ; IV. 
absent ; V. a single tooth ; VI. absent ; VII. and VIII. in single series, large and 
isolated. Maxillae dark amber, a little deeper at edge and tip, eight to nine teeth below 
the fang. The first segment considerably broader than the next. Anterior feet with 
much larger lobes than in Nereis dumerilii, the ventral being especially developed. 
Superior bristles have rather short tips ; falcate bristles have somewhat long tips, as in 
Nereis herguelensis. 
A large form belonging to the group containing Nereis dumerilii, and, like the others, 
living in a tube. The latter consists of a somewhat opaque tough secretion coated with 
coarse sand-grains, minute pebbles, and here and there small zoophytes and other 
organisms. The largest specimen measured about 60 mm., with a breadth of 6 mm. at 
its widest part. 
In the preparation the dorsum is marked in front by two interrupted light 
brown bands, and these are subsequently followed by long patches arranged trans- 
versely on each side and rather in front of the middle of each segment. A similar 
patch occurs at the posterior margin of the somite, so that the dorsum has a char- 
acteristic appearance. The light brown bands in front are due to the same arrangement, 
only a belt of pigment (widening as it goes) is present from the patch backward to 
the segment-junction. 
The head (PI. XXXV. fig. 13) is rather longer than broad in front, with two conspicuous 
pigment-bands running backward from the base of the tentacles. The latter are pale, 
and about two-thirds the length of the head. They are not much tapered. The 
’ tentacular cirri are shorter than in Nereis dumerilii, the longest in a young specimen 
extending to the eighth foot, but only to the sixth in a large one, in which the tentacles 
are also shorter than the above estimate. The eyes are of moderate size (the anterior pair 
as usual exceeding the posterior), devoid of lenses in the small specimen, less distinct and 
slightly milky in the centre in the adult. The palpi have large bases and comparatively 
small terminal bosses. 
The paragnathi (VII. and VIII.) of the basal ring are blackish, large, and arranged 
in a single series. They are seven in number, a median and three lateral, each in its 
