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It will be seen that first we have a typical example of each order, next we have typical examples of each family into which the order is divided, and lastly we have typical examples of each group into which the different families have been divided. Spaces have been provided for illustrations of the microscopic characters of each principal division, and in this part of the work I have been aided by my daughters, who have made the drawings from preparations shown by the microscope, from portions selected by myself as suitable examples; and I may say that the features of each have been as faithfully pourtrayed as was possible without colouring, which, for other reasons as well as for the sake of uniformity, it was decided to dispense with.
The series is comprised in three baywood trays or drawers, of the usual size adopted for the Museum collection of Invertebrata, measuring 29 inches by 18 inches, and 3 inches deep.
The arrangement commences with the Carnosa-sponges which have no evident skeleton; and first in order are placed those which not only are without skeleton, but have not even any spicules. Then follow those which have spicules in greater or less abundance scattered throughout the soft parts.
The next order is Ceratina—sponges which have a horny skeleton, more or less - hollow, cored with a soft, whitish granular matter. In this division the sponges are arranged in families, according to the greater or less hollowness of the fibre. The sponges in this order gradually pass into the next—the Psammonemata ; for, in addition to the granular axis, we find species whose skeleton or fibre is also cored with grains of sand and other foreign objects, which is the peculiar feature of the Psammonematous or sand-sponges.
The order Psammonemata commences with the sponge of commerce, in which the grains of sand are almost entirely absent; and it is divided into families according to differences of skeleton, depending mainly on the quantity of foreign objects introduced into the fibre; so that at one end we have sponges almost entirely free from sand, etc., and at the other end, sponges whose skeleton structure is simply a network of ropes of sand, in which the sand grains are agglutinated together with such a small quantity of horny material, that when denuded of the soft parts and dried, the whole sponge can be reduced to a handful of fine sand by very slight pressure or squeezing, a character which induced Dr. Johnston to give the species the name of “ fragilis.”
All divisions are of course empirical, for I need not say to you that no such divisions exist in nature, and consequently we are prepared to find the sand-sponges gradually passing into the rhaphidonematous sponges, or those whose fibre is cored with spicules like rhaphides. At the end of the order, therefore, are placed those sponges which not only take up grains of sand and other foreign objects from the wash of the sea, and embrace them in their skeleton structure, but which also produce spicules themselves for skeletal purposes.
The order Rhaphidonemata contains the sponges whose skeleton fibre is cored more or less with spicules proper to the sponge, or, in other words, produced by the species. This is a very numerous division, and is separated from the Holorhaphidota, or sponges whose skeleton structure is made up almost entirely of proper spicules, by an empirical line; and between the two Mr. Carter has introduced the order Echinonemata, to embrace all sponges whose skeleton structure is more or less echinated with spicules proper to the species. The last two orders are the Hexactinellida, or sponges with six rayed spicules ; and the Calcarea, whose spicules are composed of calcium.
It is not to be expected that this system or any other will satisfy everybody, but it is perhaps the best that can be adopted in the present state of our knowledge of the Class, and whatever advances may be made in time to come and we way expect very much to be done in the near future), all will admit the desirableness, indeed the necessity, of having some system to work upon. And I am satisfied that future students and observers will find their work much facilitated by having a typical collection to refer to, selected by the author of the system here adopted.
Mr. Carter, in his latest communication on the sponges collected by the Rev. H. H. Higgins in the “ Argo" Expedition to the West Indies, in 1876,* says as follows :-"I propose to identify those already known, and to name and describe those which hitherto have not been published, availing myself at the same time of this opportunity to couple with these descriptions general and classificatory remarks, aided by descriptions and references to species in the British Museum and elsewhere which will best illustrate the subject, thus endeavouring to heap up still more matter for someone to embody in a 'Manual of the Spongida,' based, if he should think fit, on my Notes Introductory to the Study and Classification of the Spongida' (Annals, 1875, vol. xvi., p. 1, &c.), since it is useless for me to commence a work of this kind now, which I can never expect to complete. Had I had, twenty years ago, the amount of knowledge of the Spongida which the opportunities and time of the last twenty years have given me, I might have done this myself, and more; but as it is, it must be left to the next generation.”
From the above we learn that Mr. Carter regards the
* See Annals and Magazine of Natural History, for April and May, 1882, pp. 266–301, and pp. 346–368, for two articles, entitled “Some Sponges from the West Indies and Acapulco, in the Liverpool Free Museum, described, with general and classificatory remarks. By H. J. Carter, F.R.S., &c., Plates XI. and XII,” containing notes and descriptions of Sponges of the “ Argo" Expedition, and Sponges collected and presented to the Free Museum by Capt. W. H. Cawne Warren, Associate of the Society.--T. J. MOORE, Curator.
work he has accomplished as so much contributed during his lifetime towards a more complete treatment of the subject byand-by, and not by any means as a final and fixed arrangement which future investigations cannot in any way modify.
Dr. HICKS exhibited a specimen, from the Museum Aquarium, of the free-swimming stage of a Jelly Fish, and also (under the microscope) a monstrosity of the embryo Chick at the thirty-sixth hour of incubation.
Mr. T. J. MOORE exhibited the following from recent additions to the Free Public Museum, lately brought from the River Plate by Mr. P. H. Rathbone :
Specimens of Salt-water Fish and Land and Fresh-water Shells, from Monte Video, collected by Mr. J. F. Bourse.
Fossil remains of Glyptodon and other extinct Mammals, from Frey Bentos, Banda Oriental, presented by Mr. C. Croker. A small box of Fossil Mammalian Bones, collected at the Cerro, Monte Video, by Mr. Conrad Möller.