more nearly like e pluteus than at the present 



tine. On the other hand on account of the resemblances 

 which exist between the larva or O.brevispina and 

 Antedon rosacea( treated of in another place )v;e nay 

 suppose a close phylogenetic relationship exists be- 

 tween them, If ? as many zoologists believe, the crinoids 

 have retained more nearly than any, other group the char- 

 acters or the primative echinoderm stock, then in the 

 Ibrvc of O.brevispina we^have on: which has retains! 

 unmodified its primative characteristics. 



But these considerations are foreign to the sub- - 

 ject natter of this paper in which the facts only of 

 development are treated. 



Tile method used in the preparation of the material 

 for nlcrcscopical stuay and which gave good results is 

 as follows: -The larvae were taken up into a pipet with 

 as little water possitl; and squirted into a snail 

 bottle containing a solution of sublimate-acetic^ 

 (98 parts sat .sol.IIgCl^ being used to 2 parts glacial 

 acetic acid). After fron two to five minutes the sub- 

 limate solution was drawn off gently leaving the larvae 

 at the bottom where they had settled. Then 50^> alcohol 

 was added which in a few minutes v.'as drawn off and re- 

 placed by 10% alcohol in which a little iodin had been 



dissolved . In a few hours this was changed for cle^r 



. muddi 



75Jb alcohol in which the larvae remained until p^sriy. 



