120 
REPORT— 1847. 
balsam, a section whicli was thick enough to be previously quite opake be¬ 
comes translucent. 
309. The skeleton of the Echinodcrmata contains very little organic nut¬ 
ter. When it is submitted to the action of dilute acid, so that the caleareoiu 
matter is removed, the residuum is very small in amount; indml, uiiIl'm tiie 
acid be so weak as <?«///to di.ssoive the carbonate of lime, the orgaaic 
matter will be also dissolved, and no animal basis will be ^parent. If,«i 
the other hand, the testa or spines of the Echinus be calcined, thci fill 
retain their form, but will he rendered oxtrem«-ly fragile. Thcfntoi: 
analysis is given by Prof, Valentin, on the authority of bis colleague, Prol. 
Brunner, as representing the composition of the. recent testa of the Eckbm. 
he proportion of organic matn.-r, however, -would seem, from tlie cipai- 
ments ot 1 rof. Valentin himself (with which my own concur), to be nukr 
too high. ^ 
Carbonate of lime . 86'81 
Sulphate of lime. i-38 
Carbonate of magnesia . O'-Sl 
Other salts and loss. 1-14 
Organic matter . g-gs 
lOO-OO 
nf V. n . ^ theEchinus is submitted to the action 
nfik '■y ^ “Ute acid, so as to leave tlie organic basis imdissolved, an examination 
ni.,i cr Slows that it posso.s.scs a structure entirely different from the ani- 
tliP « '<! shells ot the Mollusca. The reticular structure Is presen-ed; 
ncarmcp ^ bounded by a substance in which a flbrownp* 
hieh'mamiifvino-*"^ 'vith granules, niuy be discerned under asiifficicaidv 
the ccllukr nr H not at all correspond either with 
the action of described as left after 
resemblaLo tn Mollusca. Put it bears a very strop? 
-cellular," but now gJnemllr 
body of higher anim n-’akes up a considerable part of the fabric of the 
of tLir true skh. T particularly abundant in the sulMtaflW 
inata, therefore b< tf«sposed to regard the skeleton of tlie EcUnode^ 
of lime with the fihr”. con.solldated by the union of carbonaf 
perfect forra3 is whilst the shell of Mollusca (in their 
f T ^gRregatiun of cells, within which the 
higher animals —wlm«n correspond with the cpidenna 
substance, would form n n*' secreting calcareous matter instead of horjr 
former appear to r. " P”*?" mutual adhesion,^ «loes 
been calcmed. «f which the fibrous structure hs 
deposit of mineral mi I arenlur or sioiply-fibrous tissue, hr die 
union with the oryanir *" lut^hcs or areol®, but in mtiuiaie 
ologisij for it nre^Mif« ^ .-.t ** ^ condition of much interest to the phj*;' 
nial kingdom of a nriir/ "'1 • iT ^*^®'**P*c> even in this low grade of the ani- 
formation aSd growth "" impori^it share in 
'■«rio^ ‘l" of late upon the pro«ssaf «^ 
I’ror. Sharpey h=u Jatclv ho^l’ ‘'if'? bisiory of the carpi^e-cells, 
I'o Uevdoped in f.bronl to tbe welI.kno“n .hat bow 
''•■servatioiis (in which llir TmCr op!h”' “ *" ‘^^"iluge, aod he states as the 
>e developed by ihe cahifij^S,? confirm him), that 
thu, formed bevo id r ■[ ' "fibrous tissues; the edges of the crac“> 
■beyond the Innus ofthe.r cartilaginous basis, and the increase of thel«« 
