sion lens; the cause of which lay in the peculiar refrangibility of coloured rays passing through the oil, as compared with water. A vote of thanks was then passed to Dr. Pigott, and the meeting adjourned to November 9th. Donations to the Library and Cabinet from June 8th to Oct. 12th, Society. Academy. Academy. Institution. Institution. Transactions of the Northumberland and Durham Bulletins de L'Academie Royal de Belgique. 2 Parts, 1869 Annuaire de L'Academie Royal de Belgique Smithsonian Contributions to Knowledge, Vols. XIV. and XV... Smithsonian Reports for 1868 Annual Report of the U. S. Department of Agriculture United States Patent Office Reports for 1867. 4 Vols... The Orbit Phenomena of a Meteoric Fire-ball. By J. Vargasia. Boletin de la Sociedad de ciencias Fisicas y Naturales de Caracas, No. 7. Commelinacea Indicæ, Imprimis Archipelagi Indici. Die Zoophyten und Echinodermen des Ardriatischen Vegetationsverhältnisse Von Croatien. Neilreich .. Institution. U. S. Patent Office. Smithsonian Institution. Smithsonian Institution. Smithsonian Institution. Author. Author. Von Dr. A. Author. Verhandlungen der kaiserlich-königlichen Zoologisch- On the Structure and Affinities of the Genus Dicrano- The Student, Nos. 3 and 4. New Series Schäffer. 1764 10 Slides of Fresh-water Algæ, &c., prepared and mounted by Mr. W. H. Walmsley, of Philadelphia.. 44 Slides of Marine Algæ, mounted by Mr. Chas. Adcock, M.R.C.S... Academy. Author. Dr. Millar. W. H. Walmsley. Chas. Adcock. [Owing to great pressure of matter, we are obliged to go to press without either our "Notes" or Reports of several Societies.-ED. M. M. J.] THE MONTHLY MICROSCOPICAL JOURNAL. DECEMBER 1, 1870. I. On a New Anchoring Sponge, "Dorvillia agariciformis." By W. SAVILLE KENT, F.Z.S., F.R.M.S., of the Geological Department, British Museum. (Read before the ROYAL MICROSCOPICAL SOCIETY, Nov. 9, 1870.) PLATE LXVI. DR. J. E. GRAY placed in my hands yesterday morning, with kind permission to describe it, the sponge which, with an accompanyingplate in illustration of its structure, I exhibit on the present occasion. The form is a remarkable one. In external aspect it presents much the appearance of a " button mushroom" just springing from the ground, having several bundles of long filiform spicula depending from its lower surface. It may be said to be divided into two distinct portions: an upper, which takes the form of a hood, and corresponds to the "pileus" in making use of the fungoid comparison; and an inferior, bearing a rough resemblance to the stalk. The supporting skeleton of this sponge is entirely silicious, having its component elements disposed in the following order. From the interior and basal portions we find radiating in every direction dense fascicles of stout spicula having their external extremity trifid and dichotomously branching, "Bifurcated expando-ternate" Bowerbank, as shown at Plate LXVI., Figs. 6 and 7. The interlacing ramuli of these spicules alone are exposed to the surface in the basal portion of the sponge. The surface of the upper part, however, presents quite a felty appearance, which arises from a mesh-work of anchorate, hexradiate, attenuate, and other varieties of spicula which are superimposed on the outer branching extremities of the trifid forms. The attenuate and anchorate spicula have frequently a definite fascicular arrangement. Immediately beneath the surface of the hood, and connecting it with the lower portion of the sponge, is a beautiful open reticulation of the sarcode, as shown at Fig. 3. Highly magnified, this net-work presents the appearance given at Fig. 4, and is found to be almost completely filled with minute irregularly stellate spicula, isolated and still more highly magnified examples of which are shown at Fig. 5; this reticulation VOL. IV. Y of the sarcode most likely represents the porous system of the sponge, or in all probability constitutes the more important portion of it. In the firmer bands of sarcode intersecting the reticulation, as represented at Fig. 3, may also be found larger triradiate and quadriradiate spicula. The minute irregular stellate spicula are abundant in the sarcode throughout the sponge, in which also occur the small hexradiate and delicately echinate forms depicted at Fig. 10. The rootlike bundles dependent from the base are found to consist for the most part of attenuate anchorate and attenuate linear spicula, having the minute hexradiate and irregularly stellate types interspersed among them, The oscular system is very distinctly marked on the upper surface of the sponge, and, as may be observed in Figs. 1 and 2, consists of several large and unevenly distributed oval orifices, which give off branches and ramify internally throughout its substance. In the specimen figured, the largest osculum occupies the centre, having the smaller ones distributed round it; in another example which accompanied it, however, there are four or five large oscula of equal size, and numerous smaller ones all irregularly disposed. The possession of hexradiate spicula makes it necessary to refer this form to the group of the Hexactinellidæ, treated of at length in the November number of the Journal; but the oscular system and other structural characters are so entirely different from what obtains in all the species referable to that group which have hitherto been recorded, that it will be necessary to create a new division or family for its reception. This, however, with fuller particulars of its entire structure, I reserve for a future communication. The sarcode throughout this sponge is remarkably firm in consistence, and quite distinct from that which characterizes those species of the Hexactinellide with which we are at present familiar. The diverse forms of spicula seem to indicate that this species constitutes a connecting link between the Hexactinellidæ and Tethyidæ; further study of it is necessary, however, before pronouncing a decisive opinion on this point. I propose to distinguish this sponge by the name of Dorvillia agariciformis: the generic title, at the suggestion of Dr. Gray, in honour of Mrs. Dorvill, of Kingsbridge, Devonshire, a lady well known for her contributions to natural science, and more particularly for the beautiful figures she drew and etched to illustrate the 'Testacea Britannica,' and for the assistance with her pencil she rendered Col. Montague in his descriptions of sponges and other marine animals communicated to the Linnæan and Wernerian Societies. The specific one is given in consideration of its agariclike form. The specimens from which this description is derived have just been purchased by Dr. Gray, for the British Museum, with many |