1887] Zoology. 289 
Nettle-Cells.—R. von Lendenfeld has a paper on the function 
of the nettle-cells of Coelenterata in the January number of the 
Quarterly Fournal of Microscopical Science. Nettle-cells are de- 
fensive structures situated in the ectoderm, and usually also in 
the endoderm, of all Polypomedusz. Their structure is some- 
Diagram of a nettle-cell with the surrounding nucleated columnar epithelium: z, 
cilia; ce, cnidocil; e, sub-epithelial muscle-cell ; f, tangential nerve-fibre ; /, longi- 
tudinal striated muscles ; m, mesodermal supporting lamella; 7, ganglion-cell ; sf, 
nerve connecting ganglion-cell with me, nettle-cell; , uncle of Hamann ; fc, 
palpocil connected with s, sense-cell; ¢, thread coiled up inside of nettle-cell,— 
After Lendenfield. 
what complicated. They consist each of a single cell hollowed 
within to contain a long spirally coiled thread, and produced 
at the surface into a strong process,—the cnidocil,—which 
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