58 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [JuilC 14, 



should prove when fully investigated to have such a composition, 

 still it could not be regarded as a true Alcyonium, that term having 

 been adopted by Pallas, and subsequently retained by Cuvier, M. 

 Milne-Edwards and other great authorities for certain tentaculated 

 Anthozoa * . 



For certain fossil Amorphozoa, Prof. Goldfussf adopted the terms 

 Achilleum, Manon and Tragos from Schweiggerljl, who had borrowed 

 them from Pliny §. Schweigger apparently regarded the three 

 genera as solely corneous, one of his characteristics for the whole 

 group being " calx nulla" {loc. cit.). For his type oi Achilleum he 

 adopted with Phny ("ex quo penicilli") the ordinary sponge of 

 commerce; for that oi Manon, the Sp. oculata of Esper|l, a Euro- 

 pean species, and identified by Dr. Johnston^ with the HalicTiondria 

 palmata of Dr. Fleming** ; while for Tragos he gives T. incrusta?is, 

 Alcyonium incrustans of Esperf f, considered by Dr. Johnston to be 

 the well-knowTi "bread-sponge," or Ilalichondria paniceaXX- ^^^ 

 out of the three genera have therefore, according to Schweigger' s 

 types, a mineral (siliceous) skeleton, and the other, the sponge of 

 commerce, has an intermixture of earthy with corneous materials. 

 M. Goldfuss's characters for Achilleum {op. cit. p. 1) agree with 

 those given in the ' Beobachtungen,' as well as his notices of Manon 

 and Tragos, embodying however in the permanent structures the 

 large apertures alluded to by his predecessors in the superficial ge- 

 latinous or subgelatinous matter. From this statement it is plain 

 that the Atherfield fossil, ha^dng a decidedly calcareous composition, 

 cannot be generically identified with the Achilleum, Manon or Tragos 

 of Schweigger ; and Prof. Goldfuss not having alluded to the pro- 

 bable composition of the fossils assigned by him to those genera, 

 though from his adopting the characters previously given, he possibly 

 regarded the original constitution to have been corneous, it might be 

 deemed justifiable to reject, in the present case, those names without 

 farther inquiry. Moreover, the author of the article " Spongiadse," 

 before-mentioned, rightly observes, "Very few of the genera adopted 

 from Schweigger, Goldfuss and others, can be considered at all suffi- 

 ciently determined, because the constituent structures of the fossil 



* Consult M. Milne-Edwards's Memoir " Sur les Alcyons proprement dits," 

 Ann. des Sc. Nat. 2nd series, ZooL, tome iv. 1835, or Recherches sur les Polypes, 

 Mem. " sur les Alcyons," p. 1 et seq., 1838 ; also 2nd Ed. Lamarck, ii. pp. 598, 

 631 note, 1836. 



t Petrefacta, &c., pp. 1, 2, 12 et seq., 1826-1833. 



X Beobachtungen auf Naturhistorischen Reisen, 1819, Systematic Table VII. 



§ " Spongiarum tria genera accepimus : spissum ac praedurum et asperum, tragos 

 id vocatur : spissum et moUius, manon : tenue densumque, ex quo penicilli, Achil- 

 leum." (Hist. Nat. Ed. Harduini, fol. torn. i. p. 529, or Ub. ix. cap. xlv. sec. 69, 

 1723.) 



II Pflanzenthiere &c., 1791-1794, Zweyter Theil, s. 180, Spongia, pi. 1. 



i Hist. Brit. Sponges, p. 92-93. pi. 2. 



** Hist. Brit. Animals, p. 523. 



ft Op. cit. Alcy. tab. 15 apud Schweigger. Consult also Lamarck, 2nd Ed. ii. 

 p. 603, no. 16. 



XX Hist. Brit. Sp. p. 122 ; Hist. Brit. Anim. p. 520. 



