DESORTPTTON OF EPHYDATIA BLEMBINGIA. 97 



in favour of the view that the gemmule is derived from what 

 he calls an "ovi-bearing cell." In the year 1886 Goette 

 supports the view that this group of cells is the product of 

 cell proliferation (hypertrophy) (10). 



In reply to both of these views it will suffice to point out 

 that at no stage during the early development of the gem- 

 mule are there any signs of cell division. Though during the 

 very earliest stages the cells are absolutely clear (PI, 2, 

 fig. 8) I am totally unable to find the least sign of nuclear 

 division^ not to speak of fragmentation. In all cases the 

 nuclei seem to be well formed, and in no way modified. 

 Carter had not the facts required to support his view, while 

 Goette seems to have merely figured a piece of ordinary 

 sponge, indifferently preserved, as the first rudiment of the 

 gemmule. For fig. 31 (10) can hardly be explained in an}- 

 other way. It must be admitted as certain that he saw 

 flagellated chambers and canals in the specimen represented 

 in the above-mentioned figure, but it seems almost equally- 

 certain that what he saw was not the rudiment of a gemmule, 

 for the gemmule at its first appearance offers no points of 

 comparison with Goette's representation. From the con- 

 sideration of the absence of cell division, the view that the 

 gemmule rudiment is formed by that means may be set aside — 

 to say the least — as a most highly improbable one. 



The second view of the origin of the gemmule rudiment to 

 be considered is the one according to which it contains collar 

 cells and flat epithelium cells, or, as Weltner expresses it, that 

 it consists of cells from two or three germ layers. This view 

 has its most influential advocate in Goette. It was held b}^ 

 Carter also at one time, and probably by Lieberkiihn, avIio says 

 of the spherical heaps of cells he found in the sponge tissue, 

 that, besides containing Meyen's masses, they also contain 

 undoubted sponge cells. 



If the explanation given above of Goette's fig. 31 (10) is 

 correct — and it seems that it must be — it easily explains how 

 he arrived at the conclusion that all the sponge layers parti- 

 cipate in the formation of the gemnuile. Besides, it is quite 



VOL. 44, PART 1. — NEW SERIKS. G 



