1893.] MICllOSCOFICAL JOURNAL. 69 



Fig. 13. Morula stage. 



Fig. 13. Section of morula, showing the beginning of the 

 growth of the endoderm.* 



Fig. 14. Gastrula stage of Hydra (Kleinenberg). 



Fig. 15. Diagram! to explain the physiology of nettle-cell, 

 showing the ordinary columnar cells, the supporting lamella (si), 

 the pillar from it to the nettle-cell, the muscular layer (mu), 

 the protoplasm of the nettle-cell surrounding the elastic sac, and 

 a fibre running thence to the sensitive hair cell (sen). 



Fig. 16. Nettle-cell with thread ejected (from nature). 

 ( To be continued. ) 



Radiolaria. 



By Rev. FRED'K B. CARTER, 



MONTCLAIR, N. J. 



In the number of the Journal for last November my series of 

 articles on the " Radiolaria : their Life-History and their Classifica- 

 tion," came to an end. But that simply means that the task I had 

 set before myself in the summer of [891 , and which resulted in the 

 paper w^hich formed the bulk of those articles, was finished. It 

 was my aim to give a brief account of the life-history of this 

 class and a general idea of the classification of the genera found 

 by Ehi^enberg in the Barbadoes earth, taking Haeckel for my 

 guide, and I carried out my aim as well as I could. But I 

 w^ould not have the readers of the Journal suppose that I have 

 done with this subject. On the contrary, I feel that my work 

 has only just begun, and I shall hope to bring the Radiolaria 

 before the microscopists of this country again and again, for I am 

 more convinced than ever that these forms are worthy of the 

 closest study, and that any one who will devote himself to this 

 subject will become as enthusiastic as myself. And there is a 

 special reason why he should take it up, for, as far as I can dis- 

 cover, there are few workers in this country who are paying any 

 particular attention to it. The number of those who are study- 

 ing the diatoms is legion, but you can count on your two hands — 

 yes, on one hand, unless I am very much mistaken — the micros- 

 copists in the U. S. who are giving all the time at their com- 

 mand to the Radiolaria and pursuing this branch with the settled 

 intention of mastering it as far as possible. As yet, I have not 

 heard of one such, and I would most earnestly beg any worker in 

 this line to make himself known to me. There is work enough 

 for a score of others. In the November number of the Journal 

 Mr. K. M. Cunningham pleads for a distinct science, to be 

 known as " diatomology," and gives three reasons wh}' the study 



* BrauT, Zeits. f. u. Zool., vnl. 52, p. 169 ; pi. x, fig. X12. 

 fSee Von Lendenfeld, Am. Nat., 1887, p. 289. 



