Professor Macgillivray on the Cirripedia. 305 
is not a matter for which I would make a great scramble; for it is dis- 
gusting, as well as ludicrous, to see with what eagerness some people 
tear the small shreds of knowledge out of each others mouths. 
It is not very improbable that it may be Anatifa elongata of Quoy and 
Gaimard, which is said to inhabit the coasts of New Zealand, and of 
which the specific character given in the second edition of Lamarck is: 
A. testa compressa, elongato-ovali, postice subtruncata, cinereo-cceru- 
lescente, margine lutea; pedunculo mediocri, tuberculato. 
The cirri of all the Cirripedia known to me, namely about twenty 
species of the genera Lepas, Pollicipes, Otion, Cineras, Balanus, and 
Coronula, have a tube filled with fluid along the back, distinct from the 
more compressed, anterior, concave, ciliated, part. They are extended 
partially or entirely by the propulsion of this fluid. On removing the 
pressure they resume their curvature. It seems probable, that the muscles 
in the pedicle or foot propel the fluid, and perhaps there may be filaments 
for curving the cirri. At all events, the mechanism is most simple and 
efficient. 
Another fact is, that the application of heat and light changes the dark 
cclour of the epidermis, whether of the stem or pedunele, to scarlet. 
Ifthe mantle and dermal tube of the peduncle be removed from the 
darkest Barnacle, the epidermis will almost always become red in dry- 
ing. So that for all the importance which Dr Gould attributes to the 
- colour of the stem, as a distinctive character, it is really not much 
worth. 
A third and more important fact is, that on the epidermis of many 
specimens of Lepas incurvata and L. Nauta, I find a kind of small cal- 
careous spicula, which at first sight one might take to be a species of 
Pedicellaria. These objects, generally considered as organic portions 
of the sea-urchins and star-fishes, on which they are found in vast 
numbers, would therefore have to be also viewed as organic appendicules 
of Barnacles, or else distinct beings, parasitic on the Cirripedia, as well 
as the Echinodermata. It is on the membrane between the calcareous 
plates, and on the peduncle, that they occur. They do not, however, 
resemble the Pedicellariz which are seen on our Echinodermata, but 
present the appearance of single or aggregated spicula, often divergent 
or radiate, and mostly covered by a pellicle of the epidermis. Whether 
erystallizations or aggregations of calcareous particles, or organic beings, 
these objects require a more minute examination than I am able to be- 
stow upon them at present. 
Some species of the genera Cineras and Otion come next in order. 
VOL. XXXVIII. NO. UXXVI.—APRIL 1845. U 
