which I cannot pass over without remark; it is called, from the disposition of its chambers, the spirolinite, and resembles the common nautilus spirula, the crozier-shell of collectors, except that the coils, which in the recent shell are separate, are in this fossil in close apposition. Several species

Fig. 1. Spirolinites Lyellii. Fig. 2. S. Murchisoni.

previously unknown in the chalk, were discovered by the Marquis of Northampton, P.R.S. some years since, in the pebbles on the Brighton shores; and

in flints from the chalk at Kemp-town, and other places: these minute but most interesting objects having escaped the notice of less accurate and intelligent observers.

My son also has collected

Fig. 1. Spirolinites Stokesii. 2. S. Mantellii. 3. S. Lyellii.
4. S. Comptoni.

several specimens from the chalk and flints near Chichester. I have great pleasure in laying before you enlarged drawings, by his lordship, of four

species; the smaller figures indicate the size of the originals.*

24. INFUSORIA IN FLINT.-Among the almost endless diversity of forms in which those atoms of

*Note on the Sussex spirolinites, by the Marquis of Northampton :

66

I willingly comply with your desire to communicate a short note on the Sussex spirolinites, one species of which you have been pleased to distinguish by my name. I have found these fossils in flint at Brighton, Kemp-town, Rottingdean, Lewes, Hastings, Steyning, Chichester, West Stoke, and in the Isle of Wight; and one specimen in France. I have discovered about two hundred of these minute chambered shells in flint, but only two in chalk. Some of the microscopic bodies extricated from the chalk by Mr. Lonsdale, I am inclined to think are spirolinites, but others are foraminifera. I have seen, as I believe, minute nummulites in the Sussex flint. The spirolinites which I have collected constitute four distinct species. 1. The one to which you have been pleased to give the appellation of S. Comptoni. 2. Spirolinites Lyellii, distinguished by the horizontal chambers, one above the other, in the coiled portion. 3. S. Stokesii, which I name after our friend Charles Stokes, Esq.; and this name has the further advantage of pointing out the locality, West Stoke, near Chichester, from which I obtained this unique specimen, and where other spirolinites abound. The fourth vou must allow me to designate S. Mantellii. The distinctive characters of these species are too obvious to require detailed description. The transverse chambers in S. Lyellii (Tab. 55, fig. 1, and Tab. 56, fig. 3,) are a striking peculiarity of structure; in the specimen from France (Tab. 55, fig. 1), there appear indications of a siphuncle in the straight prolongation. I am inclined to believe that there are other species in my collection, but the irregularity in the fractured sections of these minute chambered shells, renders it difficult to arrive at accurate conclusions on this point.

"Castle Ashby, January 1, 1838."

"NORTHAMPTON."

animal existence, the infusoria (so called because numerous species abound in vegetable infusions) appear, many, like the cypris of which we have already spoken, possess shields or coverings, some of which are ferruginous, others calcareous, and many silicious; the yellow film seen on the surface of stagnant water is made up of these animals. The infusoria belong to many distinct families, some having a complex organization, with a nervous, muscular, and circulating system, and digestive organs highly developed. As I shall revert to this subject in another lecture, I now only wish to call your attention to the remarkable fact, that the silicious cases, or skeletons, of this class of beings, have been discovered in a fossil state; and that some deposits, for instance the tripoli of Bilin in Bohemia, consist almost entirely of the silicified remains of infusoria, of a species so minute, that a cubic inch of stone, weighing 220 grains, contains upwards of 41 thousand millions of these skeletons.* The distinguished naturalist, Ehrenberg, to whom we are indebted for this wonderful discovery, has also detected the remains of these animalculæ in chalk-flints, semi-opal, and other silicious substances; and the Rev. I.B. Reade, of Peckham,† has observed in the flints of Surrey, shields of gaillonella, a form of infusorial animal well known to microscopic

See a translation of Ehrenberg's Observations on these discoveries, in Taylor's Scientific Memoirs, Part III. † Appendix H.

observers. I shall hereafter place before you representations of several of these objects; it is sufficient for the present to have stated the fact, that entire masses of flint are composed of the fossilized remains of beings, as wonderful in their structure and organization, as any of the colossal forms of animal existence.* Some kinds of opal appear to have been formed of the dissolved silicious skeletons of these animalcules, and the more durable forms are seen preserved in it like insects in amber.†

25. CRUSTACEA OF THE CHALK.-Species of several genera of crustacea have been obtained from the Sussex chalk; in some examples I have succeeded in removing the surrounding stone, and exposing the filiform antennæ, the abdominal segments, and the tails of astacidæ. In the galt, the crustacea hitherto discovered belong to very small species. I have obtained from Ringmer, near Lewes, specimens which, in the opinion of Dr. Leach, are extinct forms, related to Indian genera. In the Speeton clay of Yorkshire, Professor Phillips has discovered several beautiful species of astacus.‡ The Shanklin sands of Kent and Dorsetshire have

* The vegetable kingdom presents us with forms equally minute. The red colour occasionally observable in the snow at Baffin's Bay, is occasioned by a species of fungus (uredo nivalis), a full grown individual of which is but 1-1600th of an inch in diameter; each square inch of the snow is therefore covered by two millions five hundred thousand fungi.—Bauer.