533 



ENCRINITES. 



ENDOGENS. 



634 



synonyms of the latter, Kentucky Asterial Fossil (Parkinson), anil 

 Encrinites florealis (Schlotheim), as quoted by Miller, and thus pro- 

 ceeds : " This is extremely abundant in many parts of Kentucky, and 

 on the margins of the Mississippi in a few places. Near Huntsville 

 they are very numerous ; and on the surface of a fragment of rock, 

 three inches long by two and a quarter inches wide, sent to the 

 Academy by Mr. Hazard of that place, I have enumerated eighteen 

 specimens of this species more or less entire, and two specimens of 

 the preceding (P. pyriformis). On another still smaller piece of rock 

 are twenty-one specimens, all in alto relievo, two of which are of the 

 preceding species. On a third fragment of. rock thirty may be 

 counted, and on a fourth upwards of fifty. That these animals 

 were pedunculated and fixed, there cannot be any doubt. We see 

 at the base of the pelvis a small rounded surface, perforated in 

 the centre for the passage of the alimentary canal, and on the outer 

 margin are very short but distinct radii of elevated lines, evidently 

 intended for articulation with the first joint of the column. The 

 column itself is always found in fragments accompanying the body 

 of the animal, but never attached to it. I think it highly probable 

 that the branchial apparatus communicated with the surrounding 

 fluid through the pores of the ambulacra by means of filamentous 

 processes : these may also have performed the office of tentacula in 

 conveying the food to the mouth, which was perhaps provided with 

 an exsertile proboscis ; or may we not rather suppose that the animal 

 fed on the minute beings that abounded in the sea-water, and that it 

 obtained them in the manner of Aicidia, by taking them in with the 

 water ? The residuum of digestion appears to have been rejected 

 through the mouth," 



Mr. G. B. Sowerby observes, that all the specimens received in this 

 country from Kentucky were changed into a sort of chalcedony or 

 chert, a circumstance which has perhaps not only prevented British 

 naturalists from forming a correct judgment of their natural affinities 

 as a family, but appears also to have had the effect of preventing them 

 from recognising the generic resemblance to the species that occur 

 here, which, bearing so much greater a similarity to some of the 

 Echinida, has caused some of our naturalists to class them together : 

 for it ia observable, he remarks, that of perhaps twenty specimens of 

 the Kentucky Asterial Fossil that he had examined only one indi- 

 vidual showed the sutures that separate what Say calls the " pelvic 

 scapular and interscapular plates or pieces." The examination of the 

 new species however suggested to Mr. Sowerby the probability that 

 part of the three unequal pieces which Say calls the pelvis, may in 

 fact prove to be centals, thus evidencing one more relation to the 

 Crinoidea. Mr. Sowerby records and describes two species, premising 

 that the circumstance of Say's first species, P. globota, having been 

 brought from England, led Mr. Sowerby at first to suppose that Say 

 might refer to one of those species that had come into Mr. Sowerby's 

 hands. Say's description, however, in Mr. Sowerby's opinion is so 

 incomplete, and the terms he has used are so vague, that Mr. Sowerby 

 had not been able to ascertain the fact, but thinks, nevertheless, 

 that ' Pelvis deep, saucer-shaped, convex,' may serve to distinguish it 

 from both. Mr. Sowerby's two species aqp Pmtremites Derbiensis 

 from Derbyshire (limestone) and P. eUiptica from near Preston in 

 Lancashire. 



In a paper (' Zool. Journ.,' vol. iv.) Mr. Sowerby changes the name 

 to Pentatrtmatitet, and records three more species, namely P. anyulata, 

 P. irtjlata, and P. oblonga ; all from the calamine mines belonging to 

 the Duke of Buccleuch, on the Lancashire side of the Hodder ; and 

 in the last volume of the ' Zoological Journal,' he describes three in 

 addition, namely P. orbifularu, P. acuta, and P. pentanyularia ; the 

 last he considers to be the Platycrinita pentanyularis of Miller, the 

 arms being imaginary in bis figure. Goldfuss describes a species 

 from the transition limestone near Dusseldorf. 



De Blainville places this genus at the end of the Crinoideans. 

 It appears to be the connecting link between the Crinoidea, and the 

 Echinid<p, but to have a much stronger relationship to the former 

 thiin to the latter. Afnrsttjiitet may be regarded as a connection 

 between the true Crinoideans and the Comatulie. 



The following is a summary of the distribution of this group of 

 animals, by Professor E. Forbes : 



"This important tribe had its greatest development during the 

 palicozoic and secondary epochs, diminishing materially towards the 

 close of the latter, and becoming scant and scarce during the tertiary 

 and historical epochs. They commence their existence with the 

 earliest sedimentary deposits, and arrive at their maximum of develop- 

 ment before the close of the palaeozoic periods. In the Lower 

 Silurian they are fragmentary, but common ; in the upper beds of 

 that formation many fine species occur often well-preserved in 

 limestone. Aclinocrintu, Cyathocnnus, Dimerocrinui, Rhodocrinus, 

 Eugcnocriniu, Taxocrintu, Trochocrinus, and Hypanthocrinui are 

 British Silurian genera. During the Devonian epoch we find the 

 genera Cyathocriniu and Platycrinu, Taxocrinu, and Adelocrinus. 

 The limestone* of the carboniferous period abound in Crinoideec. 

 Numerous species of A ctinocrinui, Platycrinus, Cyalhocrinui, Poterio- 

 crinut occur, with others of the genera Rhodocrinus, Symbathocnnun, 

 I, ill,, rttocrintu, Taxocriniu, &c. The commencement of the secondary 

 period is marked by abundance of Pentacrini, indicative of a new 

 of crinoidal forms. At Lyme Regis, where they have been 



found in great numbers, they occur associated with fossil wood in 

 such a manner, that there can be little doubt that they lived attached 

 to floating masses of wood, probably in shallows. Higher up among 

 the oolitic strata, we find the curious Apiocrinus (the Pear-Encrinite) 

 which appears to have lived attached to ancient banks of coral. 

 During the cretaceous epoch the free Crinoids begin to appear, and 

 Comatulce seem to have been not uncommon. The genus Marsupites 

 is a remarkable form of this group, and disappears before the com- 

 mencement of the tertiaries. The last of the fossil Pentacrinites 

 appear in eocene strata, but as the genus still lives it is probable 

 that intermediate species will be found. Comatulez existed during all 

 the tertiary epochs. In Britain however no trace of it has been found 

 in pleistocene strata. The supposed genera of Echinidce, Ganymeda of 

 Gray, and Glenotremites of Goldfuss, are only the cups of ComcUulce. 



" It may be noted generally respecting Fossil Crinoids 1st., That 

 all the genera of the family Actinocrinida (including such as have 

 cups composed of thin and slightly articulated pieces and having 

 much divided arms), as Rhodocrinus, Actinocrinus, Gilbertsocrimts, 

 Metocrinus, Scypaocrinus, Cyathocrinus, Platycrinus, Dimerocrinus, 

 Hypanthocrinus, &c., are confined to palseozoie strata. 2nd. That all 

 the genera of the family Poteriocrinidce (composed of such as have 

 their cups made up of large and strong segments, but in general aspect 

 closely resembling the members of the first tribe), as Poteriocrinug, 

 Isocrinus, and Symbathocrinus, are palaeozoic. 3rd. That the genera 

 of the family Pentacrinidre (characterised by the strongly articulated 

 segments of their cups and head of the column, and by the side-arms 

 of the latter) range from the triassic epoch to our own times, having 

 their maximum during the oolitic epoch. 4th. That the genera of 

 the family Apiocrinidce (characterised by the pear-shaped and articu- 

 lated summits of the stem and cup, and the naked column), as Apio- 

 crinus, Guettardocrinus, Millericrinus, Encrinus, and Eugenocrinus, are 

 secondary, and for the most part oolitic. Encrinus is a genus not 

 found in British strata, and characteristic of the trias (Musehel-Kalk). 

 It is the well-known Stone-Lily or Lily-Kncrinite of collections. The 

 genus Bonigeraiicrinui of D'Orbigny, of which two species are how- 

 ever from the chalk, is an exception to the above rule, if the remains 

 of a Crinoid, found preserved in the recent blank of the Antilles, be 

 rightly referred to it. 5th. The Free Crinoids, Oomatulida, appear to 

 have ranged from the oolitic period to the present time; for in 

 the lithographic slates of Bavaria we find several remains of animals 

 closely allied to Comatulte. This family appears to have attained its 

 greatest development during our own epoch, and as certain living 

 species are known to pass through stages exactly comparable to the 

 adult state of the Stalked Crinoid, we must regard the Comatulidie 

 as the most advanced of crinoidal forms." 



(Johnston, Physical Atlas.) 



ENDECA'NDRIA, the ninth class of the Linnsoan system of Botany, 

 distinguished by having nine stamens separate from each other. 



ENDIVE. [ClCHOKIDM.] 



ENDOCARP. [FRUIT.] 



ENDOGENITES, the name for certain Fossil Plant-Stems, as E. 

 erosa, from the Tilgate Beds. (Mantell.) 



E'NDOGENS. One of the large primary classes into which the 

 Vegetable Kingdom is divided bears this name, in consequence of its 

 new woody matter being constantly developed in the first instance 

 towards the interior of the trunk, only curving outwards in its sub- 

 sequent course downwards. That palm-trees grow in this way was 

 known so long since as the time of Theophrastus, who distinctly 

 speaks of the differences between endogenous and exogenous wood. 



But that this peculiarity is also extended to a considerable part of 

 the vegetable kingdom is a modern fact, the discovery of which we 

 owe to the French naturalists Daubenton and Desfontaines. The 

 path being thus opened, the inquiry has subsequently, and more par- 

 ticularly of late years, been much extended, especially by Professor 

 Mohl, in an elaborate essay upon the anatomy of palms. 



Mohl is of opinion that the first year's wood of an Exogen is analo- 

 gous in arrangement to that of an Endogen, the woody bundles of each 

 leaf curving upwards and outwards to the base of the leaf, and down- 

 wards and outwards towards the bark, crossing through those which 

 have been previously developed. , 



The phenomena of growth in a palm-tree may be taken as typical 

 of the endogenous structure. In the beginning the embryo of a palm 

 consists of a cellular basis, in which a certain number of cords of 

 ligneous fibre are arranged circularly (fig. 1), down the radicle, 

 deriving their origin from the plumule. Immediately subsequent to 

 germination, and as soon as the rudimentary leaves of the plumule 

 begin to lengthen, spiral and dotted vessels appear in their tissue in 

 connection with the ligneous cords ; the latter increase in quantity aa 

 the plant advances in growth, shooting downwards through the cel- 

 lular tissue, and keeping parallel with the outside of the root. At 

 the same time the cellular tissue increases in diameter to make room 

 for the descending ligneous cords (or woody bundles, as they are also 

 called). At last a young leaf is developed with a considerable number 

 of such cords proceeding from its base downwards, and, as its base 

 passes all round the plumule, consequently passing downwards alike 

 on all sides of the centre that it surrounds. Within this a second 

 leaf gradually unfolds, the cellular tissue increasing horizontally at 

 the same time ; the ligneous cords, however, soon cease to maintain 



