and fingers (see Pl. 47, figs. 1, 2, 3. and Pl. 50, figs. 1, 2, 3.,) the surface of each bone articulates with that adjacent to it, with the most perfect regularity and nicety of adjustment. So exact, and methodical is this arrangement, even to the extremity of its minutest tentacula, that it is just as improbable, that the metals which compose the wheels of a chronometer should for themselves have calculated and arranged the form and number of the teeth of each respective wheel, and that these wheels should have placed themselves in the precise position, fitted to attain the end resulting from the combined action of them all, as for the successive hundreds and thousands of little bones that compose an Encrinite, to have arranged themselves, in a position subordinate to the end produced by the combined effect of their united Mechanism; each acting its peculiar part in harmonious subordination to the rest, and all conjointly producing a result which no single series of them acting separately, could possibly have effected.

In Pl. 50 I have selected from Goldfuss, Parkinson, and Miller, details of the structure of the body and upper extremities of Encrinites Moniliformis, or Lily Encrinite, in which the component parts are indicated by letters, explained in the annexed note; and I must refer my readers to these authors for minute descriptions of the individual forms and uses of each successive series of plates.*

* "On the summit of the vertebral column are placed successive series of little bones, see Pl. 50, Fig. 4. which from their position and uses may be termed the Pelvis E, Scapula H, Costal F, forming (with the pectoral and capital plates) a kind of sub-globular body (see Pl. 48. Pl. 49. Fig. 1. Pl. 50, Figs. 1, 2,) having the mouth in its centre and containing the viscera and stomach of the animal, from which the nourishing fluids were admitted to an alimentary cavity within the column, and also carried to the arms and tentaculated fingers." From the Scapula (H) proceeded the five arms, (Pl. 50, Fig. 1, K) which, as they advanced, subdivided into hands (M) and fingers (N) terminating in minute tentacula (Pl. 50. Figs. 2, 3,) the number of which extended to many thousands. These hands and fingers are represented as closed, or nearly closed, in Pl. 48. and Pl. 49, Fig. 1. and Pl. 50

From the subjoined analysis of the compotent portions of the body of the E. Moniliformis, we see that it may be resolved into four series of plates each composed of five pieces, and bearing a distant analogy to those parts in the organization of superior animals from which they have been denominated. A similar system of plates, varying in number and. holding the same place between the column and the arms of the animal, may be traced through each species of the family of Crinoïdeans. The details of all these specific variations are beautifully illustrated by Mr. Miller, to whose excellent work I must again refer those who are inclined to follow

Figs. 1, 2. In Mr. Miller's restoration of the Pear Encrinite (Pl. 47, Fig. 1) they are represented as expanded in search of food. These tentaculated fingers, when thus expanded, would form a delicate net, admirably adapted to detain Acalaphans, and other minute molluscous animals that might be floating in the sea, and which probably formed part of the food of the Crinoïdea. In the centre of these arms was placed the mouth (Pl. 47, Fig. 1.) capable of elongation into a proboscis. Pl. 47. 6, x. 7, x. represent the bodies of Crinoïdea from which the arms have been removed.

In Pl. 50, Fig. 1 represents the superior portion of the animal, with its twenty fingers closed like the petals of a closed lily. Fig. 2 represents the same partially uncovered, with the tentacula still folded up. Fig. 3 is a side view of one of the fingers with its tentacula. Fig. 4 represents the interior of the body which contained the viscera. Fig. 5 represents the exterior of the same body, and the surface by which the base articulates with the first joint of the vertebral column, Figs. 6, 7, 8, 9, represent a dissection of the four series of plates that compose the body, forming successively the scapula, upper and lower costal plates, and pelvis of the animal. Fig. 10 is the upper extremity of the vertebral column. Fig. 11 represents the upper surfaces of the five scapulæ, showing their articulations with the inferior surfaces of the first bones of the arms, Fig. 12 is the inferior surface of the same series of scapular plates, showing their articulations with the superior surfaces of the upper or second series of costal plates, Fig. 13. Fig. 14 is the inferior surface of Fig. 13, and articulates with the first or lower series of costal plates, Fig. 15, Fig. 16 is the lower surface of Fig. 15, and articulates with the upper surface of the bones of the pelvis, Fig. 17. Fig. 18 is the inferior surface of the pelvis, Fig. 17. and articulates with the first or uppermost joint of the vertebral column, Fig. 10.

him, through his highly philosophical analysis of the structure of this curious family of fossil animals.*

From the details I have thus selected from the best authorities, with a view to illustrate the most important parts that enter into the organization of the family of Encrinites, it is obvious that similar investigations might be carried to an almost endless extent by examining the peculiarities of each part throughout their numerous species. We may judge of

* Our Pl. 47 gives Mr. Miller's restoration of two other genera, fig. 1, the Apiocrinites rotundus, or Pear Encrinite, with its root or base of attach. ment, and its arms expanded. Fig. 2 is the same with its arms contracted. Two young individuals and the broken stumps of two other small speci. mens, are seen fixed by their base to the root of the larger specimens, showing the manner in which these roots are found attached to the upper surface of the great oolite at Bradford near Bath. When living, their roots were confluent, and formed a thin pavement at this place over the bottom of the sea, from which their stems and branches rose into a thick submarine forest, composed of these beautiful Zoophytes. The stems and bodies are occasionally found united, as in their living state; the arms and fingers have almost always been separated, but their dislocated fragments still remain, covering the pavement of roots that overspreads the surface of the subjacent Oolitic limestone rock.

This bed of beautiful remains has been buried by a thick stratum of clay. Fig. 3 represents the exterior of the body, and the upper columnar joints of this animal, about two-thirds of the natural size. Fig. 4 is a longitudinal section of the same, showing the cavity for the viscera, and also the large open spaces for the reception of nourishment between the uppermost enlarged joints of the column.

At fig. 5 we have the Actinocrinites 30-dactylus, from the corboniferous limestone near Bristol. D. represents the auxiliary side-arms which are attached to the column of this species, and B its base and fibres of attachment. Fig. 6 represents its body, from which the fingers are removed, showing the pectoral plates, Q, and capital plates, R, which form an integument over the abdominal cavity of the body, and terminate in a mouth (x,) capable of being protruded into an elongated proboscis by the contraction of its plated integument. Fig. 7 represents the body of an Encrinite in the British Museum, figured by Parkinson, vol. 2, fol. 17, fig. 3, by the name of Nave Encrinite. The mouth of this specimen also is seen at X, and between the mouth and the bases of the arms, the series of plates which form the upper and exterior integuments of the stomach.

the degree, to which the individuals of these species multiplied among the first inhabitants of the sea, from the countless myriads of their petrified remains which fill so many Limestone beds of the Transition Formations, and compose vast strata of Entrochal marble, extending over large tracts of country in Northern Europe and North America. The substance of this marble is often almost as entirely made up of the petrified bones of Encrinites, as a corn-rick is composed of straws. Man applies it to construct his palace and adorn his sepulchre, but there are few who know, and fewer still who duly appreciate the surprising fact, that much of this marble is composed of the skeletons of millions of organized beings, once endowed with life, and susceptible of enjoyment, which after performing the part that was for a while assigned to them in living nature, have contributed their remains towards the composition of the mountain masses of the earth.*

Of more than thirty species of Crinoïdeans that prevailed to such enormous extent in the Transition period, nearly all became extinct before the deposition of the Lias, and only one presents the angular column of the Pentacrinite; with this one exception, pentangular columns first began to abound among the Crinoïdeans at the commencement of the Lias, and have from thence extended onwards into our present Their several species and even genera are also limited in their extent; e. g. the great Lily Encrinite (E. moniliformis) is peculiar to the Muschelkalk, and the Pear Encrinite to the middle region of the Oolitic formation.

seas.

The Physiological history of the family of Encrinites is very important; their species were numerous among the most ancient orders of created beings, and in this early state their construction exhibits at least an equal if not a higher

* Fragments of Encrinites are also dispersed irregularly throughout all the depositions of this period, intermixed with the remains of other contemporary marine animals.

degree of perfection than is retained in the existing Pentacrinites; and although the place, which, as Zoophytes, they occupied in the animal kingdom, was low, yet they were constructed with a perfect adaptation to that low estate, and in this primeval perfection they afford another example at variance with the doctrine of the progression of animal life from simple rudiments through a series of gradually improving and more perfect forms, to its fullest development in existing species. Thus, a comparison of one of the early forms of the Genus Pentacrinite, viz. the Briarean Pentacrinite of the Lias, (Pl. 51 and Pl. 52, Fig. 2. and Pl. 53) with the fossil species of more recent formations, and with the existing Pentacrinus Caput Medusæ from the Caribbean Sea, Pl. 52, Fig. 1, shows in the organization of this very ancient species an equal degree of perfection, and a more elaborate combination of analogous organs, than occur in any other fossil species of more recent date, or in its living representative.

Pentacrinites.

The history of these fossil bodies, that abound in the lower strata of the Oolite formation, and especially in the Lias, has been much illustrated by the discovery of two living forms of the same Genus, viz. the Pentacrinus Caput Medusa,* (Pl. 52, Fig. 1,) and Pentacrinus Europæus, Pl. 52, Figs. 2, 2'. Of the first of these a few specimens only have been brought up from the bottom of deep seas in the West Indies; having their lower extremities broken, as if torn from a firm attachment to the bottom. The Pentacrinus Europæust (see Pl. 52, Figs. 2. 2',) is found attached

* See Miller's Crinoïdea, p. 45.

+ See Memoir on Pentacrinus Europæus by T. V. Thompson, Esq. Cork, 1827. He has subsequently ascertained that this animal is the young of the Comatula.

VOL. I.-28