General History of the Marine Fohjzoa. 121 



sible to doubt their close relationship ; in no natural system 

 could they be kept apart. Yet the one exhibits the technical 

 characters of Vincxdaria^ and the other a mode of growth 

 which is generically distinct, according-to the older systematists. 

 If the method of the latter is adopted, they must g'o into ^\^t- 

 rent families. 



Tills case is a crucial one ; for the strongly-marked indivi- 

 duality of the zooecium leaves no doubt as to the close afiinity 

 of tlie two species, while, at the same time, the difference in 

 zoarial habit is unusually striking. 



We are led to the same result by a study of the various 

 forms which exhibit the Vincularian mode of growth. So far 

 as the zooecium is concerned they constitute a very hetero- 

 geneous assemblage. Some have the Membraniporan cell, 

 such as V. ornafa, Busk, and a number of species described 

 by Waters in his valuable paper on Australian Tertiary 

 Polyzoa* ; V. ahyssicola, Smitt, has the cell of Setosella, and 

 ranks in the Microporidan family ; V. steganoporoides, Gold- 

 stein, seems to belong to the same family. F. Neozelanica, 

 Busk, is a typical Steganoporella, one of the best-marked of 

 the Cheilostomatous genera ; while S. Smittii, Hincks, is by 

 turns a Vincularian, Escharine, or crustaceous species ! 



The conclusion to which we are almost irresistibly con- 

 ducted is that the mere fashion of zoarial growth is not a safe 

 test of affinity, that it is a very variable and comparatively 

 unimportant element in the life of the species, and that, in 

 such forms as we are now considering at least, it can give us 

 little hel]) in the construction of a natural system. 



The Vincularian is one of the most strongly marked varie- 

 ties of habit ; yet, as we have seen, we find two forms the 

 cells of which show that they are very slightly moditied deri- 

 vatives from a common ancestor, one of which is Vincularian 

 and the other crustaceous or Escharine. We are brought very- 

 much to Prof. Smitt's conclusion, " that neither the agree- 

 ment nor the diversity in the mode of building their colonies 

 will give any warrant as to the natural affinities of the higher 

 Bryozoa " (' Floridan Bryozoa,' pt. 2, p. 7). 



The Vincularian habit then, like the Escharine, I regard 

 as a condition that may be assumed (within certain limits) by 

 the most diverse species ; and the forms which exhibit it, either 

 constantly or occasionally, must be placed in the groups to 

 which their general structural peculiarities ally them. The 

 genus Vincidaria has no raisoii cfetre. 



Mr. Goldstein, in the paper referred to, urges that, as con- 



* Quart. Jouin. Geol. Soc, August 1881. 

 Ann. (& J%. N. Hist. Ser. 5. Vol. ix. 9 



