PERIVISCERAL FLUID OF ECHINODERMS. 247 



not form pseudopodia. The cytoplasm was of a homogeneous 

 color of the same shade as hemoglobin, and in it was embedded a 

 slightly ovoid nucleu-. 



In my observation- on the- genera Ciicuniaria and SlicJiopns I 

 have found these cells to be limited to the Cucumaria. For 

 re. i-< Hi.- Liiven below I h,r Us as hemocytes. 



The hemocytes of Cucumaria are flattened, biconvex di-c-, ovoid 

 in shape. The cell nieinbraiie i- pla-tic. but the cell- exhibit no 

 aniu-boid movement and ried pa--i\ely ill the perivisceral 



tluid by contraction- of the aid movement- of the body. 



The . \ top], (-in i- a hoino-eneon-, ma~- o| . , -\ ellow color in 



which i- located a -mall oval nucleus, eccen t rically placed (I 



\o). In ' tu the granular content of the nucle- 



us i- very clearly apparent I ig. 401. A mass of t: :ls pre- 



sents a crimson appearance < on i parable tot! 1 blood 



of vertebi The hen I C. jaf>o>: red bo.ly wall) 



are much larger and ui<>re mmien.us than tho-e of ( '. chronjhclmii 

 <\\ hit c body wall . < >n-e< |iiently the deep Color of the former ma\- 

 :ue ill part i" thi- dilferencr in numl 



^.lnll(l llr\di '22 , although giving no reference to the earlier 



suggestions that l' !U coulaiu ' 'oliin. can'icd on a 



Series f experimeni- on tin- content of heiuorx te- in Thyone 

 briarcu^. \\< - Union obtained from tlu-e celU to 



the >pectr and oblained a band character!-! ic of ox\ hemo- 



globin; ii|ion icduciioii tin- solution gave the >in-K b.iiid charac- 

 ter i>tic of hejiio^lc.bin and when shaken \\ ith air, the double band 

 characteristic of o\\ licino-li ,bi;i a]iprared: hemin-likt cr\ -taU 

 \\cic obtained from the content of the hemoc\ tCS, 'I'he-e eX|eri- 

 nu-nt- together \\ith -i-\t-ral other clu'inical te>ts have lei Van 

 der He\de to i "iiclude that the Mib-t.mce i> hemoglobin. As 3 

 re-lilt of these ob-er\ation- I ha\e di>i^nati-d the-e cell-. t>ju- 

 of \\hich al-o occur in Cncnmariti, the lu-moc\te-. a term which 

 is briefer and more conci-e than the appellation red blood cell-. 

 YYe may a^k if there i- any rea-oii why Oxygen-carrying < ells 

 should be present in certain of the Holothurnidca au<l not in 

 other members of thi- cla-s or other Kc-hinoilerm classes. 1 

 have surest ed earlier in thi- paper that oxygen-carrying cell- 

 may be regarded as unnece->ar\ in the . \-teroidea, Ophiuroi<lea 

 and Kchinoidea because of the relati\el\- lo\\ ox\ -en need- of the 



