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



constant shifting of specific names and corresponding con- 

 fusion. It may be mentioned that tlie course I have adopted 

 in retaining Roemer's specific name has also been followed by 

 Dr. Eauff — an independent critic. 



Prof. Duncan does not seem to be aware that even if he 

 substantiated his claim to the name he proposed as against 

 that of Roemer, there is yet another bar "to its adoption, since 

 the same species in the interval between Roemer's and Duncan's 

 work Avas described by Prof. Hall*, of Albany, under the 

 title of " Ashjlospongia inornatay The descri])tion in this 

 case is indeed very meagre, and, as no figures are given, it 

 might fairly be alleged that it is insufficient for the recogni- 

 tion of the species. That, however, the A. inornata, Hall, 

 is tlie same as Hindia fibrosa^ Roemer, 1 am fairly confident, 

 as I have myself collected from the same strata, in the locali- 

 ties mentioned by Hall, the fossils answering to his descrip- 

 tions, and they are identical with Rojmer's forms. 



The second point raised against me by Prof. Duncan relates 

 to the original mineral nature of the sponges of this genus 

 Hindia J which are asserted, in his first description of the form 

 in 1879, to have been calcareous, whilst I have placed them 

 as siliceous in the Cat. Foss. Sponges. Prof. Duncan, in 

 the September number of the ' Annals,' after full con- 

 sideration of the arguments brought forward by myself and 

 Dr. Rauff for their siliceous nature, again states his belief in 

 their original calcareous constitution, and says that I omitted 

 to notice one of the main arguments in favour of this theory, 

 viz. " the discovery of a penetrating, parasitic, unicellular, 

 vegetable organism within the canals and traversing the 

 spicules "f. The omission on my part was not from a con- 

 sciousness of the asserted fact having any important bearing 

 on the argument, but simply because I felt that it was founded 

 on errors of observation which, to spare Prof. Duncan, it 

 would be preferable to pass over in silence. 



Two reasons were brought forward by Prof. Duncan in 

 1879 1 for the original calcareous nature of Hindia : one, 

 that the carbonate of lime, of wliich the spicular structure of 

 the New Brunswick specimens now consists, was not in dis- 

 tinct crystals, but resembled that of fossils which Avere 

 originally of this mineral ; the other, that " in tlie midst of 

 the long canals, in their interspaces, and passing over the 



* ''Note on the Occurrence of Asti/Iosponffia in the Lower Ilelderberg 

 Roclis," ' 16th Annual Keport of the State Cabinet of Natural History,' 

 18G3, p. G9. 



t ' Annals/ 1886, vol. xviii. p. 228. 



t ' Annals/ vol. iv. p. 90. 



