i;s DEVONIAN FAUNA. 



This genus was established by Phillips, without definition, for the well-known 

 Devonshire fossil, which he clearly indicates and figures, though not very accurately 

 describes. 



In 1844 a second species, H. hibernica, was described by M'Coy 1 from the 

 Carboniferous Rocks. 



Mr. G. W. Shrubsole, 2 however (followed by Mr. S. R. Vine), disallowed the 

 genus, interpreting it as simply a Fenestella clothed with a coral which he 

 asserted to be also parasitic on Brachiopods and Crinoids. This statement threw 

 the genus into disrepute among European paleontologists, and caused it to be 

 omitted from such books as Zittel's ' Handbuch ' and Nicholson's 'Palaeontology.' 

 The Americans, however, do not seem ever to have been misled. Various species 

 have been described by Hall and others; and Ulrich 3 in 1890 strongly combated 

 Shrubsole's views and conclusively proved the validity of the genus and the 

 unity of its structure. He mentions at least fourteen different species be- 

 longing to it. 



More lately, in 1803, Prof. Cole 4 published a detailed description of the 

 structure of H. hibernica, M'Coy, in which he clearly showed that the Irish 

 species, like the American, was a single organism, and that the parasitic 

 hypothesis was entirely at variance with facts. The same will be seen to be the 

 case with the type species of the genus described below. It is utterly impossible 

 on the examination of sections to doubt that it is more than a single complicated 

 Polyzoon, and, indeed, even rough natural specimens from Lummation could 

 hardly fail to lead an observer to the same conclusion : the accurate adjustment 

 of the upper and the inner sides could not be imagined to be the result of 

 parasitic growth, even if the organic counection between them were not as clearly 

 seen as it is in microscopic sections. Moreover, as Ulrich has well pointed out, 

 the outer network has not a closed floor as must have been the case had it been a 

 parasite. Possibly Shrubsole might have been misled by an inaccuracy in this 

 respect in Phillips's description, alleging that the fenestrules were closed externally 

 before reaching the guard, which is certainly not the case. 



1 1814, M'Coy, ' Carb. Foss. Ireland,' p. 205, pi. xxix, fig. 7. 



- 1879, Shrubsole, ' Quart. Journ. Geol. Soc.,' vol. xxxv, p. 282. 



;: L890, L'lricn, ' Geol. Surv. Illinois,' vol. viii, p. 353. 



* 18D3, G. A. J. Cole, 'Sci. Proc. ltoyal Dublin Soc.,' vol. viii (u. s.), p. 132, pi. viii, figs. 1 — 5. 



