EEPORT ON THE ANNELIDA. 
477 
(Estrella levinseni} n. gen. et sp. (PI. XXXIX a. fig. 11). 
A curious Crustacean parasite occurs on the posterior fragment (Station 63). It 
consists of a somewhat ovate body rounded anteriorly, but presenting two prominences 
posteriorly and two ovisacs. The anterior region or cephalo -thorax is bevelled from above 
downward and backward ventrally, while dorsally a kind of collar clasps the anterior 
part of the snout. Two segments follow, the first and somewhat broader being marked 
by a transverse furrow. A narrow segment succeeds, its median region being carried 
forward in an angular manner. Posteriorly are two rounded lateral prominences for the 
attachment of the ovisacs. The tube containing: the fragment of the Annelid showed 
three ovisacs, so that it is probable another example of the parasite existed. 
Artacama, Malmgren. 
Artacama challengericB, n. sp. (PI. LI. fig. 6 ; PI. XXVIIIa. figs. 23«, 6, 24, 25). 
Habitat. — Dredged at Station 149, in several localities, e.g., in Betsy Cove, lat. 
49° 8' S., long. 70° 9' E., at a depth of 40 fathoms; off Royal Sound, lat. 49° 28' S., 
long. 70° 30' E., in 25 fathoms; off Caj^e Maclear, January 21, 1874, in 30 fathoms; 
and a fragment off London River, in 110 fathoms. 
Specimens measure 75 mm. in length, with a diameter at the large part in front of 
8 mm. 
In the character of the cephalic region, body, and number of the bristle -tufts, this 
form corresponds with Artacama probosciclea, Malmgren. The bristles (PI. XXVIIIa. 
figs. 23a, b) agree very closely with the figures given by Malmgren, but differ from 
the Canadian forms in having a shorter tip, the terminal region being much more 
attenuate in the latter, and the wings narrower. The bristles are also pale in the 
present form. The broader wings in the new species are as evident in the longer (a), 
as in the shorter series {b). 
The hooks, again (PL XXVIIIa. fig. 24), present a different structure from those 
figured by Malmgren [Artacama probosciclea), so that, unless we are to suppose 
serious inaccuracy in these figures, the forms seem to diverge. In that procured by the 
Challenger, four teeth at least occur in one series above the great fang, and there are 
traces of a fifth. The great fang is largely developed, so that the crown appears small 
in comparison with it, whereas in Malmgren’s figure the crown is high and the great 
fang small. A well-marked mucro projects from the margin below the fang, while in 
^ After G. M. E. Levinsen of Copenliagen, the author of various papers on the Annelida, and especially of an 
excellent one entitled Oni nogle parasitische Krebsydr, der suylte hos Annelider, Vidensk. Meddel. f. d. nat. Foren. i 
Kj^benhavn, 1877. 
