suppose that they are capable of a more varied action, and one that may perhaps add to the momentum of the masticating organs. Hence we may conjecture that the animals destined to form their nutriment, may be larger, so as to require more exertion and force, both to take and to masticate.

In the other Order, the structure of the Balanites seems to indicate merely the protrusion and employment of their tentacles; and being usually attached to floating bodies, such as the hulls of ships, or parasitic upon locomotive animals, riding as they do upon the back of the turtle, the dolphin, and the whale, they may visit various seas in security, and feast all the while, with little trouble and exertion, upon animalcules of every description, the produce of arctic, temperate, and tropical seas.

With respect to their place in nature, it seems not quite clear whether they should be regarded as leading from the Molluscans, with which Cuvier arranges them, towards the Crustaceans, and they certainly seem to have organs borrowed from both; their shells and mantle in some degree from one, and their palpigerous mandibles and jointed organs, proceeding in pairs from a common footstalk-like the interior antennæ of the lobster-and knotty spinal chord from the other but with respect to their jointed organs, I must observe that they still more

1

closely resemble those of some of the Encrinites, like them being fringed on each side, though not with organs of that description. A learned naturalist, Mr. W. S. Mac Leay, is of opinion that the Echinidans, or sea urchins, exhibit some approximation to the Balanites. If, indeed, we compare the genus Coronula with an Echinus, we shall discover several points in which their structure agrees. We learn from Lamarck, that the pieces of the so called operculum, which close the mouth of the former shell, are affixed rather to the animal than to the shell. Thus the operculum, in some sort, represents the jaws of an Echinus, though consisting of fewer pieces, and the tube appears divided into alleys, like the crust of that animal. These circumstances seem to prove some affinity between the Cirripedes and Radiaries; they appear also to have some points in common with Savigny's Nereideans, especially Amphitrite.3 Weighing all these circumstances, I have thought it best to place the Cirripedes immediately before the Entomostracan Crustaceans.

But what if these Cirripedes should at last prove to be, not the guides to the great Crustacean host, but its legitimate progeny? This has been asserted, at least partially, by a modern zoologist, who has assigned his reasons for this

singular and startling opinion. I will not say the thing is impossible-for with God all things are possible-but it certainly appears in the highest degree improbable. That a Zoea should become a crab is sufficiently extraordinary, and an opinion, as Latreille remarks, which, if it be not erroneous, has great need of support from experiment but that a locomotive animal, gifted with eyes and legs, should, by an extraordinary metamorphosis, in its perfect state, become a barnacle, without head, eyes, or locomotive organs, can never be admitted till confirmed by repeated experiments of the most able and practised zoologists, so as to place the matter beyond dispute. I by no means, however, mean to assert that Mr. Thompson did not think he saw what he has stated, in both cases, to take place, but he was probably deceived by appearances in some such way as he states Slabber to have been."

A single fact, observed by Poli, is sufficient to overturn this whole hypothesis. This illustrious conchologist relates that he had an opportunity of examining the immense fecundity of the sessile barnacles. "In the beginning of June he found innumerable aggregations of them, covering certain boats that had been long stationary, which, when closely examined, were so

minute, that single shells were not bigger than the point of a needle; and that from that time they grew very rapidly, and arrived at their full size in October." These very minute ones must have been hatched from the egg, and not produced from larves.

With regard to the functions and instincts of these Cirripedes, very little has been observed. We see from the above account of them, that, like many other animals amongst the lowest grades of the animal kingdom, they are furnished with particular organs adapted to the capture of animalcules and other minor inhabitants of the deep, which they help to keep within due limits. Probably they act upon the substances to which they attach themselves, and promote the decomposition of shells, and other exuviæ of defunct animals, and also of the rocks and ligneous substances on which they take their station. Of this we are sure, that they work His work who gave them being, and assigned them their several stations in the world of waters.

CRINOÏDEANS.

In the deepest abysses of the ocean, it is probable, lurks a tribe of plant-like animals, to judge from its numerous fossil remains, abounding in genera and species that are very rarely

seen in a recent state, and which, from a supposed resemblance between the prehensory organs or arms, surrounding the head or mouth of several species belonging to the tribe, when their extremities converge, to the blossom of a liliaceous plant, have been denominated Encrinites and Crinoideans. It was not my original intention, as little or nothing was known with respect to the habits and station of the few recent ones that have been met with-except that one has been taken in the seas of Europe, and three in the West Indies, namely, near Martinique, Barbados, and Nevis-to have introduced them into the present work, but having subsequently seen fragments of a specimen, taken either in the Atlantic or Pacific, I am not certain which, and upon examining it under the microscope, finding evident traces of suckers on the underside of its fingers, and of the tentacles that form its fringes, a circumstance I found afterwards mentioned by Ellis, and which throws some light upon their economy, I felt that I ought not to pass them wholly without notice, and finding in the Hunterian Museum a very fine specimen which does not appear to have been figured, for the figure given by Ellis seems to have been taken from Dr. Hunter's specimen, now at Glasgow, and Mr. Miller's from a specimen of Mr. Tobin's, now in the British Museum, by the kind

1 From κρίνον, a lily.

2 PLATE III. B. FIG. 2.