ON THE ANGUILLULIDA. 161 
quire to be transferred to a distinct though nearly allied genus. Its present position 
may be looked upon merely as provisional. 
27. ODONTOBIUS, Roussel. 
Gex. CHAR. “ Body thread-like; anterior extremity more or less narrowed; posterior 
obtusely or sharply pointed, ending in a small papilla. Around the mouth and on 
anterior part of body are several cirri. On the hinder part of the body of the 
male, around the genital opening, are one or two rows of roundish integumental 
prominences. 
“ Skin colourless or of a yellowish-green colour, occasionally iridescent. External in- 
tegument smooth or transversely striped. (Esophagus cylindrical, widening slightly pos- 
teriorly ; external layer or sheath composed of a finely granular mass, or eylindrical cells. 
“ Vagina variable in position. Lateral lines present. Gland (ventral ?) of anterior part 
of body doubtful. Tail-glands consisting of an agglomeration of cells. 
“ Two spicules, with an anterior accessory organ!, or two pairs of spicules, one large 
and one small.” — Hberth, Unters. über Nemat. p. 27. 
This description is the one given by Eberth, which I have inserted rather than that 
of Roussel, from its containing more details, though even these are insufficient accurately 
to characterize and fix the position of the genus. Eberth naturally enough objeets to 
Diesing's having in his recent * Revision der Nematoden” placed this genus amongst 
his subfamily Anguillulide, since Roussel’s Odontobius was distinctly stated to be pro- 
vided with cirri around the mouth. Eberth is, however, himself uncertain what 
systematic place to assign to this genus, but says that he includes in it several free 
Nematoids which, from the appearance of small teeth? in the mouth, are distinguished 
from those of Amblyura, Phanoglene, Enchelidium, and Oncholaimus, and, through the 
want of ocelli, from those of Enoplus. 
Whether the original animal described by Roussel de Vauzème, and found by him in 
or on the mucous membrane about the base of the whalebone in Balena Australis, is 
rightly included amongst the free Nematodes is a point about which I am still doubtful ; 
but, as it seems quite possible that one of these animals might be met with in such a 
situation, I have retained it amongst them, and have refrained from altering the designa- 
tion of three of the species placed by Eberth in this genus, though one of them seems to 
differ in some important respects from the other two. 
l. O. cert, Roussel. 
Odontobius Ceti, Roussel de Vauzéme, in Annal. des Sc. Nat. 2 sér. i. 326, tab. ix. 1-5 A; et Froriep’s 
Notiz. xxxvii. 1, figs. 3-6 ; Isis, 1836, p. 512.—Siebold, in Wiegmann's Archiv, 1835, i. 336.—Nord- 
mann, in Lamarck’s Anim. sans Vert. 2% édit. iii. 669.—Dujardin, Hist. Nat. des Helminthes, 292. 
“ Corpus capillare, extremitate caudali involuta. Caput corpore continuum. Os termi- 
nile, orbieulare, dentibus corneis 3-6. Penis....; apertura genitalis feminea ..... 
Longit. ad 217. 
' This seems only to have been met with in Odontobius acuminatus, which I have transferred to the genus Anti- 
Coma, so that the latter part of this sentence only must now be considered as applicable to the genus Odontobius. 
2 H $ x A 
He omits to mention these in his generic description given above. 
VOL, xxy, 
