PERIVISCERAL FLUID OF ECHINODERMS. -"39 



brane and were allowed to remain in a live box for twenty-four 

 hours, so that the leucocyte- would have a chance to take up the 

 c.trmine particle- Al the end of this time, a piece of the body 

 wall, I cm. square, was removed from the aboral surface of each 

 -penmen. The -imens were then put into a live 



and o! tions were made over a period of four week- upon 



the < hanges which were taking place in tin ' ed area. When 



! it was noted that a membrane v. dually 



the opening in the body wall. Thi- membrane \\a- icd- 



dish in color as conti -.\ith the green i-h color of the -urround- 



i.ody wall, and : I llv from the margin of the open- 



ing BO that tin- dimini-hed slowly in diameter. In -even 



oft ening in the body wall was 1 in 



t\\o \\eek-. At tir-t the membrane closing the opening was very 



delicate, but : lally became firmer ami in >evcral -pi'cimni- 



Jiriicil. 1'lii- ph. i- tou^henin:^ of the mrmbrane 



iin-.l dining the third \vrck. It was then noticed tint >krlr- 



tal mairrial b-^aii '11 the margin of the membrane 



which-/ with the original cut surface. Purin^the 



fourth \\t-ck tin- df|),~iti.)ii nf -keletal matt-rial \\cnt furtlu-r and 

 ral individuaU -ho\\cd a portion of reK-n-ratrd test. At 

 thi- time tin- ti--iu- ;>enin^ was remo\ed lK,iu - -\rral 



-pc. iiut'ii-. spread OUt on a nd studied in tin- frr-h condition. 



Tin- wholi- ma-- liad a crim-mi color and \\ ' i tan^lrd hbrou- 

 COnsistency in \\hich \\CP irent leu ntainii 



miiu- granule- \\hich had fornu-d more or It--- if a -yncytimn. in 

 \\hich the cell boinida: ndistinct. Se\eral piece- i.f the 



membrane and the adjacent body wall were pi ion- 



iu- in order to determine the relation of the cell- to the repl 

 inent of the -kelet.in. Thc-e pieces wi ; 1 ilcified and a series 



of -ei tiou> made. 



1 i^uic J^ i- a semi-diagrammatic drawing of a vertical -ection 

 through tin- regenerated membrane and a portion of the adjoin- 

 in- body wall, the -tructute of the latter having been disi'iissed 

 above In tin- membrane thei- gions of ditlereti- 



tiation. The region m'-t di>tal to the te-t and forming the 

 center of the membrane is thick and reddi-h in color, thi- color 

 beiiu due to the |>re-eiK'e of minute particles of carmine in the 

 cells which make up the -\iic\tial reticulum of the membrane 



