156 The Blue Ci/ancea. 



sons. Only a day or two ago I was engaged in capturing some 

 lovely specimens of Chrysaora; a lady of my party, in lifting 

 one, complained of being stung, while I lifted them without the 

 slightest sense of such a phenomenon. So it is with some 

 Anemones, the tangled snake-like locks of Anthea cereus may 

 be handled by a man with impunity, while the tenderer skin of 

 women and children smarts and reddens with the contact.* 



* The subject of the poison-apparatus in a kindred group of animals I have 

 treated in considerable detail in my Aetinologia Britannica (Ihtrod. pp. xxii. 

 — xl.) I hope it may not be considered out of place if I here cite some observa- 

 tions of an American zoologist, confirming some of the most important of my 

 conclusions, and adding other information of much value. Professor Henry James 

 Clarke, of Harvard University, Cambridge, Mass., in a very able article, entitled 

 " Lucernaria, the Ccenotype of Acalephoe," describes the cnidee of this organism 

 in the following terms : — 



" The nettling organs or lasso cells, 'which crowd the globular tips of the 

 tentacles, are of two kinds, and both are imbedded in the intercellular substance 

 which fills the spaces between the columnar cells of the outer wall. One kind * 

 consists of an oval, thick-walled vesicle about l-2000th of an inch long, or a little less, 

 one end of which is introverted and projects in the form of a stout hollow shaft 

 along the axis of the cell, about four-fifths of its length, and then, rather suddenly 

 thinning into a slender thread, which is also hollow, it bends upon itself, returns 

 nearly to the aperture of the cell, and, pressing closely against the inner face of 

 the cell-wall, it forms a close coil, which terminates at the end opposite the mouth 

 of the introversion. When the coil of thread is ejected, which is accomplished by 

 sliding through the hollow axial shaft, which, in its turn, retrovcrts also, just as 

 the finger of a glove is turned inside out, the whole aspect of the apparatus is 

 changed. The oval cell is considerably diminished in size, and from its aperture 

 the enormously enlarged hollow shaft projects in a straight line ; the half of the 

 Bhaft next the cell is cylindrical, and half as broad as the latter, with a slight 

 expulsion where it joins the mouth of the cell ; the distal half abruptly expands 

 into an oval form, half again broader than the cylindrical portion, and rapidly 

 tapers into a smooth trihedral, twisted thread. The oval part of the shaft is 

 endowed with three equidistant spiral rows of setae, which number about a dozen 

 in each nnv. The seta? are comparatively large, and in length equal two-thirds 

 the broadest diameter of that part of the shaft from whence they project. Each 

 row makes but one turn above the shaft, and terminates as if in continuation of 

 the angles of the trihedral thread. There is not the least trace of Betas or pro- 

 jections of any kind upon the trihedral thread, but it continues, with a very 

 gradual taper, perfectly smooth to the blunt termination. The angles of the 

 thread appear, at first glance, as if they might be spiral rows of seta* ; but a most 

 careful and prolonged examination with ono of Spencer's j-inoh objectives con- 

 vinces me that they are truly the angles of a twisted trihedral filament. The 

 nt of the thread is from twenty to twenty-lour times the length of the cell. 

 The other kind of nettling cell is much more simple in structure, but yet more 

 remarkable, The introverted shaft is very slender, in foot no larger than the rest 

 of tin- thread. It dues not project into the axis of the cylindrico-oval cell, but 

 pretiei close tO the tide OI the latter, and extends four-fifths of the way to its 



opposite end, and then, bending abruptly upon itself, the thread passes with a 

 long curved sweep nearly to the aperture of the cell, from whence it again returns 

 with another long sweep, which u repeated eight to ten times, until the inner 

 face of the cell-wall it lined i>y a (dose coil which winds lengthwise instead of 

 transversely, as il does in the other kind first described. When extended the 



thread is Ironi twelve to fourteen times the length of 1 lie cell. It tillers not the 



letisi sign of appendages of snj kind, bul is simply a smooth round Blamenl of 

 uniform thickness throughout, excepl at the end, where it tapers slightly and 



terminates in a blunl tip. Tin II itself, when retroverted, ia Boneiblj diminish I 



in size, and narrows rapidly into I he prolonged filamentary portion. It would 



