452 Mr. W. Clark on the Animal of Kellia rubra. 
XLVI.—On the Animal of Kellia rubra. 
By W. Crarx, Esq. 
To the Editors of the Annals of Natural History. 
GENTLEMEN, Norfolk Crescent, Bath, May 5, 1849. 
I see you to allow me the insertion of a few observations, in 
reply to Mr. Alder’s last paper on Kellia rubra in the May num- 
ber of the ‘ Annals.” | 
That gentleman has stated the result of his re-examination of 
the animal of Kellia rubra with great candour, observing that 
“in all cases” I have described “the parts very correctly.” I 
feel pleasure in the corroboration of my examination of this very 
minute bivalve by so competent an observer, though we differ as 
to their uses. But however far apart our opinions may be, we 
will not forget in our disputations the prayer of the nymph 
Arethusa,— 
** Doris amara suam non intermisceat undam.” 
I do not think it will be difficult to show that the anterior 
tube-like fold of the mautle of Kellia rubra is not a special 
branchial organ, according to Mr. Alder’s views, and which he 
still retains. 
It must be borne in mind that the mantle of Kellia rubra is 
open from the posterior branchial slit to its anterior termination. 
The open fold in question is merely a prolongation of that mem- 
brane ; and when the animal opens its valves, it must receive, 
like the Mactre and Veneres, or any other bivalve with an open 
mantle, the currents of sea-water ; and in closing then, a great 
part thereof, after bathing the branchiz, is ejected from the 
aperture of ingress, and only a portion of it passes out by the 
posterior orifices. 3 
These remarks will show that I did not use the words 
*‘ branchial and anal, as applied to these apertures, in a literal 
and restricted sense.” I am not aware I have said anything to 
warrant this inference. Mr. Alder has misunderstood me. I 
only stated that the posterior branchial slit in Kella rubra is 
both a receiver and expeller of water; and this view I firmly ad- 
here to. I never intended to state it was the only one, when 
the contrary fact is so evident in Kellia rubra. 
Mr. Alder observes, that, agreeably to the “ known ceconomy 
of the bivalves, the inhalant is always kept distinct from the ex- 
halant current, and admitted by a separate aperture from that 
by which the latter is expelled.” This position is, I think, incor- 
rect; as in those bivalves with open mantles the currents of 
water enter by the great pedal orifice or rima magna of the 
mantle, to aérate the branchiz, and the greater part of the im- 
PEPSI EELS 
