600 
MR. HUXLEY ON DOLIOLUM AND APPENDICULARTA. 
he expressly states he might, except for its peculiar motion, have confounded the form 
he describes*. 
MM. Quoy and Gaimard-I-, altogether denying the existence of Otto’s genus as a 
distinct form, appropriated his name for two species of tunicate animals observed by 
them at Amboyna and Vanikoro, and which they justly recognized as being very 
closely allied to the Salpce. 
Of these two species, DoUolum denticulatum and DoUolum caudatum\, the former 
is the only one with which I have met. 
MM. Quoy and Gaimard give only the following short description : — 
Its form is nearly that of the vessel from which we have derived its generic name, 
that is to say, it is enlarged in the middle and narrowed at its two extremities where 
the openings are situated. The anterior opening is somewhat projecting and denti- 
culated like a crown. Eight circles in relief surround the body at nearly equal 
distances. They have rather a polygonal than a circular form, and are probably 
vessels. In the interior the branchia is visible, divided into two portions, which have 
their oblique lamella* upon a central vessel, as in the Pectinibranchiata. Near the 
union of the two divisions posteriorly is the heart, and between them (?) a vessel, the 
aorta, ascends ; not far from the heart is a transparent nucleus. This is all that the 
vivacity of the mollusk, which bounded like an arrow through the water, allowed us 
to make out of its organization.” 
Although I cannot think that MM. Quoy and Gaimard have done well in appro- 
priating Otto’s name to an animal confessedly different from that which he de- 
scribes, it will perhaps cause least confusion to follow their example. 
The specimens which I examined were taken in the South Pacific, a little to the 
northward of Sydney, N.S.W., between Sydney and New Zealand, and in consider- 
able numbers just at the entrance of the Bay of Islands. 
89. DoUolum denticulatum, figs. 5, 6. — A small transparent body, varying in length 
from one-sixth to one-third of an inch, and looking very much like a barrel open at 
each end, which swims by contracting its whole body, and forcing the water out at 
one or the other extremity. 
The apertures are considerably less in diameter than the central cavity. The 
anterior {d) is produced into a sort of tube, with about twelve rounded dentations, 
* Prof. E. Forbes informs me that a body answering precisely to Otto’s description, was found by him, occur- 
ring in considerable numbers, on the coast of Scotland, and was eventually discovered to be nothing more than 
the detached sipbonic tubes of Solenocurtis strigillatus. 
t Voyage de I’Astrolabe. Zoologie, t. iii. part. 2. p. 599. 
X Little more than a description of the outward form is given by MM. Quoy and Gaimard of the DoUolum 
caudatum, but it strikingly agrees in everything with what one of the associated forms of the singular genus 
Anchinaia might be supposed to become if set free ; unfortunately, the description of the latter genus itself is 
very scanty. See note (60.) 
Has the DoUolum denticulatum itself been ever an attached form? From certain appearances (90.) this ap- 
pears very possible. 
