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ECHI'NATE. | (echinatus, Latin.) 



E'CHINATED. j Bristled like a 

 hedge-hog; set with spines; having 

 sharp points or spines. 



ECHI'NIDAN. A fossil belonging to 

 the class Echinoderms. Professor 

 Auckland states that the family of 

 echinidans appears to have extended 

 through all formations, from the 

 epoch of the transition series to the 

 present time. 



ECHI'NITE. The fossil echinus, or 

 sea-urchin. Echinites vary greatly 

 both in form and structure, and are 

 arranged accordingly into many 

 sub-genera; they are all marine. 

 The chalk formation abounds with 

 these fossil shells, some of which 

 are exceedingly beautiful from their 

 elegant and minute decorations. 

 The Ananchytes cretosus, a sub- 

 genus, is found in some places in 

 shoals, and in every condition from 

 the youngest to the oldest age. The 

 Spatangus cor-marinum, another 

 sub-genus, silicified, is frequently 

 found on our shores and in our 

 gravel-pits, and the spines of the 

 different sub-genera, detached from 

 the shells, are very numerously 

 dispersed throughout the chalk. 

 The various opinions entertained 

 of the real nature of echinites are 

 curious and amusing. Rumphius 

 believed that they, as well as belem- 

 nites, fell from the sky. Monnius 

 supposed that they were the petri- 

 fied eggs of serpents. The Romans 

 imagined they were the eggs of 

 toads, or petrified toads themselves, 

 or that they fell from the clouds 

 during heavy rains and thunder. 

 Some authors supposed that they 

 were figured stones, to which 

 nature had assigned their peculiar 

 form, and these and various other 

 absurd notions were entertained 

 until the time of Aldrovandus, who 

 asserted the true origin of these 

 fossil bodies. 



ECHI'NTJS. (echinus, Lat. e^u/os, 

 Gr.) The sea- urchin, or egg. The 



echinus is included in the order 

 Echinodermata, being covered by 

 a hard and coriaceous skin. The 

 shell is spherical, and composed of 

 an immense number of polygonal 

 plates, closely fitted to each other, 

 and has attached to it many spines 

 or prickles, which serve as instru- 

 ments of motion. The mouth of 

 the echinus is placed beneath, and 

 is provided with several triangular 

 teeth. Some species of the echinus 

 are edible, more especially the E. 

 Esculentus. The echinus feeds 

 principally on small shell-fish, 

 which it seizes with its tentacula. 



ECHI'NODERMS. Simple aquatic ani- 

 mals, with a radiated, globular, or 

 elongated body, covered with a 

 spiny shell or coriaceous skin. 

 They are entirely marine, slow- 

 moving or fixed, predaceous, and 

 commonly provided with a dis- 

 tinct nervous, muscular, sangui- 

 ferous and respiratory system, and 

 organs of sense. They are termed 

 echinoderms, from the surface of 

 their skin being covered generally 

 with calcareous spines, whether 

 the surface be calcified or calca- 

 reous. Prof. Grant. 



ECHINODEBMATA. The seventh class 

 of the sub kingdom Annulosa. 

 This class comprises seven orders, 

 namely Holothuridse, Echinidea, 

 Ophiuridae, Asteridea, Crinoidea, 

 JBlastoidea and Cystidea; the two 

 last, in italics, are entirely extinct. 



ECHINA'NTHUS. The name given to a 

 section of Catocysti by Leske. The 

 genus echinanthus comprises all the 

 echinites of this section. Of this 

 genus there are many species. The 

 echinanthus was named Scutum 

 by Klein. The shells are of an 

 irregular figure, resembling a buck- 

 ler. On the base, which is concave, 

 five grooves pass from the margin, 

 and terminate at the mouth in the 

 centre. Five rays ornament the 

 upper part. The mouth is placed 

 in the centre of the base, and is of 



