8 
THE VOYAGE OF H.M.S. CHALLENGER. 
Family III. Chlidoniad^e. 
Character. — Zocecium composed of upright, free, segmented stems, springing from a 
stolonate network. From the segments, after the first bifurcation, arise lateral branches 
consisting of chains of zooecia arising from the back near the summit. Zocecia bicamerate ; 
unarmed. 
Clilidonia, Savigny. 
Chlidonia, Savigny [1811], d’Orb., 1850. 
Eucratea, Audouin. 
1 Vorticella, Linn., Esper. 
Cotliurnicella, Wyv. Thoms. 
Character. — Free portion of the zooecium composed of segmented tubular stems, with 
distant short branches, each springing from one of the internodes of the stem, and giving 
off numerous uniserial chains of zocecia, one rising from the back of another near the top, 
and all looking one way. Zooecia gibbous, pyriform, or attenuated downwards. Orifice 
prominent or subtubular, semicircular, lower lip entire, straight. The cavity of the zooecium 
divided into two chambers, the hinder of which is much curved, and alone communicates 
with the orifice and lodges the polypide. 
This very remarkable form, originally named Chlidonia} by M. Savigny, was after- 
wards renamed Eucratea by Audouin. It is, however, quite distinct from that genus, 
and M. d’Orbigny was fully justified in returning to the original appellation. As remarked 
by M. d’Orbigny (Palseont. Frany, p. 40), Chlidonia is clearly distinguished from Cateni- 
cella and Catenaria by its general habit ; and its peculiarities appear to me to be 
such as fairly to entitle it to become the type even of a distinct family. 
Each of the lateral branches supporting the tufts of zooecial chains, springs from a 
distinct short forked internode of the non-celliferous main stem, whose internodes, as 
remarked by M. d’Orbigny, represent aborted zooecia. The stem may, in fact, be regarded 
as a much developed radical tube, and in like manner each secondary branch and the 
chains of zooecia are manifestly nothing more than successive internodes, which in the 
latter are dilated into habitations for the Polypides. Another remarkable peculiarity, 
though not one altogether confined to this genus, is seen in the partition of the interior of 
the zooecium into two distinct chambers, apparently having no communication between them. 
Chlidonia cordieri, Audouin (sp.) (PI. XXVIII. fig. 11). 
Eucratea cordieri, Audouin, Exp], i. p. 243, Savigny, Egypte, pi. xiii. fig. 3. 
Chlidonia cordieri, d’Orb., Palaeont. Frany., p. 40. 
Cotliurnicella dceddla , Wyv. Tlioms., Nat. Hist. Rev., vol. v. p. 146. 
Character. — Zooecia small, much attenuated or tubular downwards. 
Habitat. — Station 186, Cape York, 8 to 11 fathoms, coral mud. 
1 Only at the bottom of the Plate. 
