LUCERNARI^. AND THEI R ALLIES. . 115 



(he great depth of color of the anchor is due largely to those enormous masses of 

 intra-cellular 'pigment. The tint varies in different individuals, but is uniform, 

 ■with varying intensity, in the same body, the latter being either altogether green, 

 or orange, or purple, or blue, etc., and not a combination of any of these colors ; but 

 sometimes is apparently so, as, for instance, when a light purple or violet umbella 

 seems to have black anchors, the latter, though, when examined under a slight 

 magnifying power, turning out to be of an intense, concentrated, dark purple. 

 Notwithstanding the remarkably abrupt changes in depth which the gastro- 

 ])hragma exhibits at irregular intervals throughout tlic colletocystophore, the com- 

 ponent cells neither increase nor decrease in.numbers, but always remain combined 

 in a single stratum, simply varying in depth according to the greater or less abrupt 

 thickenings or thinnings of the layer (see ^j 113). 



§ 28. Histology of the Caudal Dish {% 115) {figs. 118, 119, 120). 



212. The Ectophra-jma (^f 63, 194). — Since this is the only layer wliich is modi- 

 fied differently from those of the peduncle proper, which are described in a pre- 

 vious section (§ 25), we shall confine ourselves to it alone. As in the anchors, so 

 here the cells are prismatic in form, but proportioi>ately much broader and exceed- 

 ingly small, when contrasted with those of the former. Their share, though, in 

 the formation of the layer is considerably less, because they are obscured and over- 

 laid almost entirely by the nearly close ranks of coUetocysts and nematocysts ; in 

 fiict, a profile view of a section of this layer {fig. 118,/') presents the appearance 

 of being composed, at least for two-thirds of its depth, almost entirely of these 

 two last-mentioned bodies (o, /)• A face-view {fig. 119) is, therefore, a much 

 better exemplification of the true state of relationships here. By that we learn 

 tiiat there are but very narrow areas, next the outer surface of the layer, wliich are 

 occupied by the normal, prismatic components of the layer, and the rest is filled up 

 by irregularly alternating coUetocysts {fig. 118, a) and nematocysts (/). The inner 

 third of the layer is purely cellular, and the outer or distal two-thirds is com- 

 pounded as described above, yet still there is but one stj-atiim of cells proper ; tliose 

 alternating with the imbedded bodies being the longest, and extending from the 

 proximal to the distal surface, and those overlaid by the nematocysts and coUeto- 

 cysts abutting against the latter with their distal ends. The coUetocysts (a) are 

 not more than one-tenth or one-eighth the diameter of those of the anchors {fig. 97, 

 ((), excepting here and there a few of equal size, but they are far more closely 

 packed together, and thus make up in point of numbers what they lack in size. 

 They are treated of in extenso in the section on the prehensile organs (§ 30). The 

 nouatocysts (/), which serve to partly fill up the intervals between the coUetocysts, 

 are excessively small, and hardly recognizable as prehensile organs of that kind ; 

 but they are conspicuous simply because they are numerous, although looking more 

 like granules than urticating organs under a magnifying power of several hundred 

 diameters {figs. 118, 120, /)• 



