REPORT ON THE HEXACTINELLIDA. 99 



The following seven genera are not yet sufficiently known to enable their systematic 

 position to be determined, but they all appear to belong to the family Eu2)lectellida), and 

 hence are treated of here. 



Genus 1. Ilabrodictyum, Wyville Thomson. 

 This genus contains only one species, Ilabrodictyum speciosum. 



Habrodictyum speciosum (Quoy and Gaimard). 



1833. Quoy and Gaimard, Voyage de TAstrolabe, Zool., vol. iv. p. 302. 



1836. Deshayes and Milne-Edwards in Lamarck, Animaux sans Vertfebres, vol. ii. p. 586. 



1849. Owen, Trans. Zool. Soc. Lond., vol. iii. p. 205. 



1865. Bowerbank, British Spongiadse, vol. i. p. 174. 



1 866. Gray, Ann. and Mag. Nat. Hist, ser. 3, vol. xviii. p. 487. 



1867. Gray, Proc. Zool. Soc. Lond., 1867, p. 530, 531. 



1868. "Wyville Thomson, Ann. and Mag. Nat. Hist., ser. 4, vol. i. p. 114. 



1869. Bowerbank, Proc. Zool. Soc. Lond., 1869, p. 323. 



1872. Gray, Ann. and Mag. Nat. Hist., ser. 4, vol. ix. p. 442. 



1873. Carter, Op. cit., ser. 4, vol. xii. p. 349. 

 1873. Gray, Op. cit., ser. 4, vol. xiii. p. 284. 



Quoy and Gaimard ^ gave a description and figure of a form designated Alcyoncellum 

 speciosimi which differed essentially from any sponge then known. The genus Alcyon- 

 cellum had been some years before, 1830, defined by Blainville'^ in the following manner : — 

 " Corps fixe, mou, subgelatineux, soUdifie par des spicules tricuspides, phytoide, a 

 branches peu nombreuses, cylindriques, fistulaires, terminees par un orifice arrondi, a 

 parois epaisses, composees de granules reguliers, polygones alveoliformes, perces d'un pore 

 k I'exterieure et a I'int^rieure." 



The generic definition is followed by this note ^ : — " Espece L'alcyoncelle specieux, 

 A. speciosum, Quoy et Gaimard, Zoologie, Astrolabe, msc." As the following " obser- 

 vation " adds : — " Ce genre a ete etabli par Mm. Quoy et Gaimard pour un corps 

 organise, rapport^ dans leur dernier voyage et qu'ils ont bien voulu soumettre h notre 

 observation. Quoique sa forme rappele un peu celles des cellaires, il est cependant 

 evident, que c'est aupres des alcyons et des eponges, qu'il doit etre place. Mais ensuite, 

 pour determiner, si c'est un alcyon proprement dit ou un Spongiaire, il faudrait savoir. 

 si chaque grain celluliforme contient un polype ; toutefois, comme cela nous paralt peu 

 probable, nous nous sommes determine h en faire un faux alcyon ou un spongiaire." 



The description of Alcyoncellum speciosum, Quoy and Gaimard, is, on the other 

 hand, just as published in 1833 by Quoy and Gaimard,* for the genus {Alcyoncellum) : — 



1 Voyage de la Corvette rAstrolabe, Zool., 1883, vol. iv. p. 302-303, and Atlas, vol. ii., Zoophytes, pL xxvi. fig. 3. 



2 Diet. d. Sci. Nat., vol. Lx. p. 492. 3 Blainville, loc. cit, p. 492. 

 * Voyage de I'Astrolabe, Zool., p. 302. 



