Echinus

“ When the formation of the skeleton is accomplished, the typical larva of our Echinus is built up; it is called the “pluteus” (Fig. 4) . Though it is far from being the perfect adult animal, it has an independent life of its own; it feeds and moves about and does not go through any important changes of form for weeks. But after a certain period of this species of independent life as a “larva,” the changes of form it undergoes again are most fundamental: it must be transformed into the adult sea-urchin, as all of you know. ”

“ The size of the new-born Echinus is not nearly equal to that of one of these plates, and the [Pg 192] progressive increase of the plates by deposition on their edges has certainly taken several years to accomplish. [65]
The same result is inferrible from the structure of the spines with which every plate is armed. Each of these is a very long cone of calcareous matter, arranged in minute oval chambers, divided by thin glassy walls, and deposited particle by particle from the thin stratum of living flesh with which each has been invested from its first embryonic development. ”

“ According to a certain writer, there are some foreign species of the Echini remarkable for possessing spines, which act both as offensive and defensive weapons. 'On one occasion' (this writer says) 'when searching for a fish in the crevice of a coral rock, I felt a severe pain in my hand, and upon withdrawing it, found my fingers covered with slender spines, evidently those of the Echinus, of a grey colour, elegantly banded with black. ”

“ For in Echinus this system is seen in its most elaborate and efficient form; in the common Star-fish the suckers are still the most important organs of locomotion, though the muscularity of the rays has begun to tell upon the development of the specially ambulacral system, the suckers not being so long or so powerful as they are in Echinus. Lastly, the Brittle-stars and Comatulæ have altogether discarded the use of their sucking feet in favour of the much more efficient organs of locomotion supplied by their muscular rays ”

“ But although we have few varieties, those which do establish themselves on a coast seemingly so ungenial for others of their kind, such as the Echinus, and our common Star-fish, for instance, thrive well and are very abundant. The class of Echinoderms includes five orders, viz. Crinoids, Ophiurans, Star-fishes, Sea-urchins, and Holothurians. ”

“ The common Echinus of our sea-coasts (Echinus sphæra) , known by the name of Sea-egg, Sea-urchin, or Sea-hedgehog, presents the typical characters of this order of Radiata, which differs from the Crinoids and Star-fishes in the absence of arms. ”

“ Yet the animal is able to progress slowly by means of its spines, which are used to prop and push the globe-like shell along in some continuous direction. If a lighted match be held in front of the moving animal, as soon as the echinus comes close enough to feel the heat, all the spines begin to make the creature move away in the opposite direction. There is an urchin-like form of echinoderm called spatangus, which differs from the echinus in having shorter feet and longer spines. ”

“ It is curious that as the echinus grows he continually sends forth a substance from the interior which simultaneously increases the sides of all the plates which form his shell, and thus he never finds his coat too small for him. The spines which appear so rigid when he is dead, he can move when alive in any direction, and they are an excellent substitute for feet; while he can put forth tentacles from the centre orifice, which serve him as hands. ”

“ Above this the tr ache lion or necking curves over, constructing what is known as the apophyge up to the fillets, round the base of the echinus, which forms the transition to the square abacus. The varying curve of the echinus, from the earliest times down to the later examples, is shown in the article on mouldings. The relative proportions of the lower diameter and the height of the columns vary according to the date of the example, in the early examples the column being just on 4 diameters high, in the Parthenon nearly 51/2 diameters, and in the Temple of Jupiter Nemaeus 61/2 diameters high. ”

“ The Aetolians got possession of the town some time after, perhaps by Macedonian assistance.] to the Aetolians? from the Thebans taken Echinus? [Footnote: The Echinus here mentioned was a city on the northern coast of the Maliac gulf in Thessaly.] Is he not marching against the Byzantines his allies? From us—I omit the rest—but keeps he not Cardia, the greatest city of the Chersonese? Still under these indignities we are all slack and disheartened, and look toward our neighbors, distrusting one another, instead of the common enemy. ”

“ Agassiz, to whose great kindness I am indebted for much information on the subject, informs me that there are other star-fishes, in which one of the three arms of the forceps is reduced to a support for the other two; and again, other genera in which the third arm is completely lost. In Echinoneus, the shell is described by M. Perrier as bearing two kinds of pedicellariæ, one resembling those of Echinus, and the other those of Spatangus; and such cases are always interesting as affording the means of apparently sudden transitions, through the abortion of one of the two states of an organ. ”

“ For while a Star-fish is provided with flat, flexible, and muscular rays, comprising a small and light mass in relation to the motive power, an Echinus is a rigid, non-muscular, and globular mass, whose only motive power available for conducting the manœuvre is that which is supplied by its relatively 277 feeble ambulacral feet. It is, therefore, scarcely surprising that unless the specimens chosen for these observations are perfectly fresh and vigorous, they are unable to right themselves at all; they remain permanently inverted till they die. ”

“ Take, for instance, the case of the righting manœuvre. The effect of cutting out the 317 nerve-ring is that of entirely destroying the ability to perform this manœuvre in the case of the majority of specimens; nevertheless about one in ten continue able to perform it. Again, if an Echinus is divided into two hemispheres by an incision carried from pole to pole through any meridian, the two hemispheres will live for days, crawling about in the same manner as entire animals; if their ocular plates are not injured, they seek the light, and when inverted they right themselves. ”

“ Echinomma, 257.
⁠aculeatum, 258.
⁠cidaris, 257.
⁠diadema, 258.
⁠echinidium, 257.
⁠sphærechinus, 258.
⁠toxopneustes, 259.
⁠trinacrium, 258.
Echinosphæra, 638.
⁠datura, 638.
Ectolithia, lxxii.
Elaphococcus, 227. ”

“ A number of vigorous Echini were thoroughly shaved with a scalpel over the whole half of one hemisphere, i.e. the half from the equator to the oral pole. They were then inverted on their ab-oral poles. The object of the experiment was to see what the Echini which were thus deprived of the lower half of three feet-rows would do when, in executing their righting manœuvres, they attained to the equatorial position and then found no feet wherewith to continue the manœuvre. ”

“ Quintus looked down in silence.
“You speak of God,” he said at last. “Which God do you mean, Eurymachus? Jupiter, whom our forefathers worshipped, is to you a mere idol. What name then do you give to the Divinity, who commands your love? And what proof have you, that he too is not a false God?”
“My lord,” said Eurymachus, “our God has no name by which he is known. A name is used for distinction, and to mark a difference from others of the same, kind; but He is one alone and eternal from the beginning. ”

“ There is a matchless suite of fossil Echinidæ in the British Museum, which has been arranged and named by Mr. S. P. Woodward, and is now the most instructive and interesting collection extant. It contains examples of the following genera, viz., Ananchytes, Echinocorys, Echinolampas, Holaster, Galerites, Cidaris, Diadema, Acrosalenia, Glypticus, Disaster, Pygurus, Clypeaster, Scutella, Salmasis, Echinocyanus, &c. There is also a good series of echinital spines.
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CHAPTER X. FOSSIL FORAMINIFERA—MICROSCOPICAL EXAMINATION OF CHALK AND FLINT.
"Where is the dust that has not been alive?" ”

“ Quintus sat silent for some time; he seemed to wish to reflect at leisure on all he had heard, and no one disturbed him.
“My friend,” he said at last: “I too am ready to help you in my way, as honestly as Cneius Afranius—but first tell me one thing. Is Eurymachus still in Rome?”
“In the neighborhood.”
“And you will not send him farther off as speedily as possible?”
“It is impossible, my lord,” said the old man sadly. “Stephanus has set every means to work. Hundreds of watchmen and slave-catchers are on the alert; notices on the walls offer large sums for the apprehension of the fugitive ”

“ It is to no mortal, but to the gods alone that you have to confess your crime. Humility before the gods is no dishonor....”
“Your gods are not mine,” cried Quintus vehemently. “A confessor of the true God can never sacrifice to Jupiter Capitolinus.”
“Who is the true God, but he whose care and rule we see, wherever we turn our eyes, and feel in our souls? Are you so utterly degenerate, that you have learnt to confound the great universal spirit—whom our fathers worshipped as Jupiter, the Father of Light—with a mortal—with a Jewish revolutionary, whom the imperial governor silenced by death?” ”

“ By far the most abundant Cretaceous Echinoderms, however, are Sea-urchins (Echinoids) ; though several Star-fishes are known as well. The remains of Sea-urchins are so abundant in various parts of the Cretaceous series, especially in the White Chalk, and are often so beautifully preserved, that they constitute one of the most marked features of the fauna of the period. From the many genera of Sea-urchins which occur in strata of this age, it is difficult to select characteristic types ”

“ Do not I know it by my own experience?”
“It is worth trying, at any rate,” said Quintus. “But now allow me to breathe the fresh air; I am suffocating in here.” And as he spoke he unbarred the door and quitted the room.
“You must dissuade him!” said Nerva, as the door closed upon him.
“He is mad,” said Cinna. Then, turning to Aurelius, he went on: “You, my friend, go now and mingle with the guests. Amuse yourself, refresh and rest yourself. You are young, and youth claims its dues. To-morrow—you know—at the house of Afranius....” ”

“ Before him stood Caius Aurelius, with eight soldiers of the northern army.
“Quintus!” he cried, with open arms. “The gods be praised! Rise, noble Cornelia. Why do you gaze at me, as if you saw a ghost? I am Aurelius. I have brought you freedom.”
“Caius?” stammered Quintus, almost speechless with surprise and new-born hopes. “You here—tell me, what has happened?”
“Rome is ours. More than half the Praetorian guard have sworn fidelity to Cocceius Nerva. The Palatium was invested an hour ago. You shall hear it all, but oh! my senses are reeling...! ”

“ He shuns neither violence nor treachery; and he sins unpunished, for he has powerful supporters. It is said that Parthenius, the chamberlain....”
“Enough!” interrupted Quintus. “His hour too will come; it would be well for your safety, no doubt, that it should strike soon.”
“We are not idle,” said Glauce. “My father has now found what he long hoped for in vain; a just and learned patron, whose liberality shrinks from no sacrifice. You must have heard of Cneius Afranius?”
“Cneius Afranius? I know him very well, and have met him repeatedly in the house of Cornelius Cinna. ”

“ Fossil Sea-Urchins, or Echinites.
Fig. 1. The shell of a Turban Echinite (Cidaris saxatilis, of Parkinson) , broken in two, and each piece imbedded in the same fragment of flint. From Kent.
Fig. 2. A round Buckler Echinite (Echinodiscus (Clypeaster) subrotundus, of Parkinson) , from Italy.
Fig. 3. The upper surface of an Echinite (Spatangites (Disaster, of Agassiz) ovalis, of Parkinson) ; from Scarborough.
Fig. 4. View of the upper, and fig. 5, of the lower surface of an Echinite, (Spatangus (Hemipneaster, of Agassiz) radiatus, of Parkinson,) from the cretaceous strata of St. ”

“ As the animal has a geometrical form of perfect symmetry, we might suppose that when it is placed upon its pole, all the 281 five rows of feet would act in antagonism to one another; for there seems nothing more to determine either the action or the inaction of one row rather than another. Indeed, if there were any moral philosophers among the Echinoderms, they might point with triumph to the fact of their being able to right themselves as an irrefutable argument in favour of the freedom of the Echinoderm will. ”

“ I confess myself guilty. The God of the Nazarenes is the only true God. Your Jupiter is a foolish, ridiculous image.”
The governor shook his head in bewilderment.
“Follow me then,” he said doubtfully; “I will inform the city-prefect.”
“Quintus—farewell!” cried Cornelia, with a triumphant glance at her lover. “Think better of it, Quintus! or else we meet again face to face with the beasts in the arena!” ”

“ The second letter was from Cornelia, Quintus’ betrothed, and ran as follows:
“Cornelia embraces her dear Quintus a thousand times. Here I am in Rome again, my beloved! My term of banishment to that odious desert at Tibur is ended. But, woe is me! Rome is dead and deserted too since you, my treasure, my idol, linger still far from the Seven Hills! Oh! how glad I am to hear from your father, that he is recalling you from Baiae sooner than was intended. Oh! Quintus, if you felt only one thousandth part of what I feel, you would fly on the wings of the storm to the arms of your love-sick Cornelia. ”