THE CCELOMIC FLUID IN ACANTHODEILIUS. 585 



alcoliol, in ether, and in potash; and this opens up another 

 question — the relation of the two kinds of cells. 



To this I am not prepared with any suggestion, but it is 

 fairly evident that one is derived from the other. 



Before leaving these eleocytes, reference may be made to 

 Mr. Picton's observations on the corpuscles of the coelomic 

 fluid of Am phi trite, of which he figures (figs. 50, 52) 

 examples, which appear to agree closely with those of Oligo- 

 cliseta. Further, he states that in some of the eleocytes in 

 which little fat has accumulated there are ''strongly defined 

 granules of yellow pigment" (p. 290), which are represented 

 in his fig. 51, where each appears ns a highly refringent 

 granule in the centre of a "' vacuole," similar to the condition 

 noted in the " lamprocytes " of Octochtetus; in fact, the 

 figure of the whole corpuscle, with its vacuolated structure, 

 might stand for such a cell. 



In this paper the author gives an account of the series of 

 chemical tests applied by him to the cell-contents of heart- 

 body and other cells, in a series of Polychseta. 



With regard to the linocy te or thread-containing cells : — 

 these seem to have been observed in coelomic fluid for the 

 first time by Goodrich — in Enchytra3us hortensis. His 

 account of the reactions of the thread agrees very closely with 

 those enumerated above; but he states, with some apparent 

 doubt, that the thread is dissolved in boiling potash. The 

 fortu of the cell and of the thread itself is dift'erent, however. 

 The "thread-containing cell" of Enchytr^us agrees with 

 the "granular cells" in containing highly refringent 

 globules, and he states (p. 58) " that the thread itself 

 appears to be formed at the expense of the granules/' 

 though he allows that the appearance upon which he relies 

 may be deceptive. 



In Octochaetus it does not appear that there is any 

 relation between either the "granules" or the globules on 

 the one hand and the "thread" on the other; we have seen 

 that the characters of the cells are entirely different, and 

 while the " eleocyte " and the "lamprocyte" may be, and 



VOL. 44, PART 4. NEW SERIES. P P 



