REPORT ON THE HEXACTINELLIDA. 181 



the skeleton of the adherent polype, Valenciennes expressed the belief that we have here 

 to deal with spougoid spicules, and that the polypes occurring upon these belong to the 

 group of the Zoantharia, and are to be looked upon as parasites.^ 



Gray* at once defended his views, and pointed out that it was improbable that the 

 polypes should always be found associated with the sponge, or that the association 

 should be so intimate as it was, and noted further that the axis skeleton of the well- 

 known Gorgonise presents a concentric lamination similar to each of the long sUiceous 

 threads. 



In a further communication by Gray on the same subject,' the family of the 

 " Hyalonemidse " is regarded as a family of corals, with the single genus Hyalonermi, with 

 characters which agree, essentially, though not verbally, with the above diagnosis of the 

 senus given in 1835. 



Gray reported the presence of ring-shaped or spiral projections on the outer surface 

 of the concentrically laminated long spicules, and communicated the result of the 

 chemical analysis of these by W. Prout and T. J. Pearsall, both of whom gave their 

 composition as hydrated silicic acid. 



It is curious that Gray here designates as Hyalonema mirabilis the only known species, 

 which he had described in his first communications as Hyalonema sieholdii, and that he 

 quotes the Synopsis of the British Museum, 1830, p. 118, as relevant literature. This 

 quotation, which has passed into se%'eral later papers by other observers, is proved to be 

 false, inasmuch as in the library of the British Museum no edition of the Synopsis of 

 the year 1830 is to befouud, while the edition immediately preceding, published in 1827, 

 contains no communication on Hyalonema, either at the page cited or an}^"here else. 

 Since I was unable, for want of time, to continue the search further during my stay in 

 London, I requested Mr. Stuart 0. Ridley to do so, and the result of his accurate examin- 

 ation — for which I here express my best thanks — has shown that in none of the earlier 

 editions of the Synopsis of the British Museum, down to edition xxvii. of the year 1832 — • 

 in which the words already quoted are to be found on page 79 — does any communication 

 on Hyalonema occur. This notice, however, is repeated in the following editions — xxvii. 

 to xl. — ^without essential change, and further observations are first added in edition xli. of 

 the year 1840. No alternative is therefore left but to believe that Gray made a false 

 quotation from memory, or had perhaps in error taken the note on his museum label or 

 such like for the scientific name which he himself had adopted. This is important, inas- 

 much as it is not the specific name Hyalonema mirahilis used by Gray in the year 1857, 

 but that already given by Gray himself to the same species in 1835, Hyalonema 

 sieholdii, which has the priority. 



I Milne-Edwards and Jules Haime, Monograph of the British Fossil Corals, j). 81. 

 - Ann. and Mag. Nat. Hkt., ser. 2, vol. vi. p. 306. 

 ^ Proc. Zool. Soc. Land., 1857, pt. xxv. p. 278. 



