476 MARIA M. OGILVJE GORDON. 



I demonstrated by descriptions and illustrations (p. 123^ 

 124, 138; figs. 13, 14, 17, etc.) that several layers of calico- 

 blasts were shed from the ectoderm of the polyp during each 

 period of active growth, and that these adhered more closely 

 with one another than with the previously or subsequently 

 formed series of layers, yet that each layer Avas complete in 

 itself; farther, that each individual calcifying part originally 

 limited by organic walls (which I termed cell-walls), retained 

 its individuality during its transformation into a " calcareous 

 scale/' and could be obtained apart from its neighbours as 

 an individual entity. 



It creates rather a confusion of ideas when M, Krempf 

 implies that von Heider had held the view that the " calcareous 

 scales" were the "skeletons of calicoblasts" — since von Heider 

 was not aware that the "juxtaposition of calcareous 

 scales formed the corallum," and he could not possibly 

 have claimed for these skeletal elements, as I did, that they 

 were transformed cell -pro ducts, and represented the 

 "fibre-containing cells," which he had observed in the cellular 

 tissue, and termed calicoblasts (cf. Ogilvie, 1. c, p. 125). 



The second part of M. Krempf's account in the ' Comptes 

 Rendus ' describes a series of observations which bear upon 

 the relationship of the ectoderm to the layer of skeletal ele- 

 ments immediately external to it. Before quoting from 

 M. Krempf, I shall indicate the direction followed in my 

 investigations of this subject. 



My sections of the soft parts corroborated the observations 

 of Dr. Fowler and Dr. Bourne (cf. Ogilvie, 1. c, pp. 101-2). 

 Comparing my sections of the soft parts with njy prepara- 

 tions from the corallum, I was able to observe farther that in 

 these positions, such as the periphery of the calyx, which 

 corresponded to the most closely nucleated and actively- 

 dividing parts of the ectodermal tissue, the calcareous scales 

 were most thickly piled in the corallum, and their organic 

 remnants ("dark points") most closely grouped — sometimes 

 in little rings, sometimes in rows. 



" In all cases we have simply to do with centres and axes 



