ORYCTOLOGY. 



Of a different form have been named ly- 

 coperditae, fungitae pilcati, &c. A fossil 

 Alcyonium has even been described by 

 Volkmann and Sclieuchzer as a fossil 

 nutmeg 1 . A fossil A Icyoniurn of a conical 

 form is represented, Plate I. fig. 6. 



The Encrini and Pentacrini have been 

 always, and very properly, considered as 

 the most curious of the fossil Zoophytes. 

 The Encrinus (Plate I. fig. 3) possesses 

 the distinguishing- character of having its 

 ppine, or, as it has been generally called, 

 its tail, composed of cylindrical or orbi- 

 cular vertebrae, pierced through their 

 centre, and marked with diverging striae 

 on their articulating surfaces. On the 

 superior termination of these is placed 

 the base of the body of the animal, form- 

 ed of five trapezoidal bodies, termed by 

 Rosinus articuli trapezoides, which in- 

 close five small bodies, which form the 

 centre of the base ; the whole of these 

 forming that which Rosin us denominated 

 the pentagonal base. From each of these 

 proceed six other bodies, on the two last 

 of each scries of which are placed the 

 arms of the animal, which divide into fin- 

 jgers ; from the internal surface of these 

 proceed almost innumerable articulated 

 tentacula. This fossil has long possessed 

 the name of the Encrinus, or stone lily ; 

 its resemblance to that flower having led 

 to the suspicion that it was a petrifaction 

 of a flower, approximating in its form to 

 the lily : its animal origin is however now 

 completely ascertained. Indeed, if a 

 doubt had remained, it would have been 

 removed by the circumstance of the ani- 

 mal membrane, or cartilage, having been 

 actually discovered in the fossil, (" Or- 

 ganic Remains of a former World," vol. 

 li. p. 166.) Several other species of this 

 animal are also described in the work just 

 referred to; but hitherto no recent "ani- 

 mal has been found which can be referred 

 to this genus. 



The fossil Pentacrinus differs from the 

 ?Sncrinus, in its vertebrae being of a pen- 

 tagonal form, and in its arms, fingers, and 

 tentacula being capable of being much 

 more widely spread and extended than 

 are those of the Encrinus. It appears 

 from Mr. Parkinson's account, that there 

 pe several species of this fossil, the ex- 

 istence of some recent species of which 

 have been also ascertained. 



The encrinital vertebrae (Plate I. fig. 

 7 a) have been hitherto termed trochitae 

 when separate, and entrochi when con- 

 nected in a series, (Plate I. fig. 7.) The 

 single vertebrae of the Pentacrinus have 

 been distinguished as asterise, (Plate I. 

 fig. 8 o) ; and when united together they 



have been termed columnar asteriae, 

 (Plate 1. fig. 8.) 



Of the Asteriae, orStellae Marinx, some 

 very few specimens have been found fos- 

 sil ; but they occur very rarely, and have, 

 in general, been found in a condition too 

 imperfect to allow of any positive opinion 

 being formed, respecting the species to 

 which they belong. 



The fossil Echini are very numerous, 

 upwards of forty species, known only as 

 fossils, being enumerated by the illus- 

 trious Linnaeus; to delineate, therefore, 

 even those most deserving of notice could 

 not be here well accomplished ; a cir- 

 cumstance, howevtr, which is not so 

 much to be regretted, since, though ma- 

 terially different, they approach very 

 nearly in their general form to the recent 

 species. Those which possess a hemi- 

 spherical, or a nearly orbicular form, with 

 large mamilla-like protuberances, and 

 the anus disposed vertically, have been 

 distinguished as the turban echini (echini 

 adores) , those which resemble a shield 

 or buckler in their figure, are termed 

 the shield echini (clypeii Jfleinii) ; and 

 one of the largest of these has been nam- 

 ed the polar stone by Dr. Plot (Plot's Ox- 

 fordshire, p. 91.) When of a depressed 

 circular form, with the anus in the edge 

 of the inferior part, they are the fibulae 

 of Klein; of a conical form, the eagle- 

 stone of the Germans (conuli, Kleinii}; 

 with a circular base, the quoit echinus 

 (discoidei, Klcinii}. When the base is an 

 ;icute oval, the mouth and anus being at 

 the opposite ends, they are termed the 

 helmet echinis, (cassidcs et gaiex, A'!ciidi\, 

 and when heart-shaped, with a sulcaled 

 superior surface, they are called snake's 

 hearts (spatangi, Klcinii.} 



The attempt to particularize the va- 

 rious species of fossil shells which have 

 been found would require a large volume: 

 all that can be here done is to notice 

 some of those which totally differ from 

 any which exist in a recent state, and to 

 offer some few remarks on those which 

 appioximate, or are perhaps similar to 

 some of the species which are known in 

 a recent state. 



With respect to the state in which fos- 

 sil shells are found, it is necessary to re- 

 mark, that, in some situations, shells 

 which have been buried for ages, by the 

 natural changes which the surface of the 

 earth has undergone, are found very little 

 changed, except from the loss of colour, 

 and having been rendered extremely fra- 

 gile; that in other situations the substance 

 of the shell has been so injured, as to be 

 reduced to very small fragments, an<i 



