Dr. G. J. Hinde on the Genus Hindia. 69 



original spicular structure of the sponge has almost entirely- 

 disappeared, and the radiating canals and interspaces between 

 the spicules are infilled with solid silica. When thus pre- 

 served tlie fossil has a most deceptive resemblance to a minute 

 Favositoid coral which has been silicified, and it is therefore 

 no matter for surprise that even so experienced a palaeontologist 

 as Ferd. Roemer *, who had not seen the form in any other 

 state of preservation, should have regarded it as a coral with 

 minutely perforated walls. His description of the characters 

 of the specimens is clear and explicit, and the accompanying 

 figures accurately represent its external form and internal 

 structure, so that even small fragments of the fossil could be 

 recognized from them. It is not Roemer's fault if his faithful 

 description of the forms which he named ^^ fibrosa " does not 

 correspond with that given later by Duncan of the same 

 fossil in a different state of preservation. A mere cursory 

 glance at Roemer's figures would lead one to suspect the 

 identity of the silicified forms from Tennessee with the calcified 

 ones from New Brunswick described by Duncan. This 

 identity can be readily demonstrated by placing a specimen 

 from this latter locality in dilute acid, when, by the removal 

 of the spicular structure, it presents the same appearance as 

 the Tennessee examples. In one specimen in my possession 

 the same result has been effected by natural means, so that in 

 one part of it the structures described by Roemer as '^fibrosa^^ 

 are clearly shown, and in another part those which Duncan 

 placed under the specific name " spJueroidah's.^^ 



Under these circumstances I submit that Roemer's clear 

 description and figures of these silicified fossils justly entitle 

 his specific name ^' fibrosa^'' to be retained for them, and that 

 the error he made in placing them as corals does not, accord- 

 ing to the recognized rules of scientific nomenclature, warrant 

 its rejection in favour of the subsequent designation of Prof. 

 Duncan. If such a substitution were allowed there would be 



* Ferd. Rcenier does uot stand alone in making this mistake. The 

 description of this same fossil was the first attempt I myself made at 

 palfeontological work, and in complete ignorance that it had been previ- 

 ously noticed by Ro3mer I also put it down as a coral ! I had the less 

 excuse for the error since my specimens were not silicified. Fortunately 

 the Geological Society, to whom my paper and specimens were sent, only 

 published the former in abstract. The mistake I made taught me to 

 use the microscope and greater caution in future work. It is stiU more 

 remarkable that even after both I and Ferd. lioemer had, independently 

 of each other, publicly acknowledged that our supposed coral was a true 

 sponge. Dr. Steinmann, a palajontologist of some pretensions, should 

 boldl}' declare that the same fossil had not a single characteristic feature 

 of a sponge, and that it ouglit to be relegated to the same genus of 

 Fawaite-coxsXs in which Roemer had originally placed it. 



