AJfD PHYSIOLOGY OF THE SPONGIAD^. 
1103 
Professor Owen in favour of his proposed genus JEuplectella is based, not upon one only, 
but upon a series of errors ; and as he has not attempted to characterize his own genus, 
while that of Alcyoncellum, Quoy et Gaimard, is regularly described in the ‘ Histoire 
Naturelle des Animaux sans Vertebres’ by Lamaeck, 2nd edit. voL ii. p. 589, printed in 
1836, it is evident that the generic name of the French authors must take precedence 
of that proposed by Professor Owen. 
The following is the generic description of MM. Quoy et Gaimakd : — 
“ Gem’e Alctoncelle {Alcyoncellmn). 
Spongiaire lamelleux, dont la charpente est formee de filets tres delies, accoles les uns 
aux autres et entre-croises de maniere a former des mailles nombreuses, arrondies, 
assez regulieres, et semblables a celles d’une dentelle.” 
In this generic description the material of which the sponge is formed is not in the 
shghtest degree indicated, and the description of its structural peculiarities is so general 
that it vdll apply equally well to almost every known fistulose sponge. 1 have there- 
fore thought it necessary to arrange the sponges of this genus with their congeners in 
material and mode of construction, and to reconstruct the generic characters so as to 
endeavour to limit the genus within definite bounds. I propose therefore to substitute 
the following characters for those of the French authors. 
Alcyoncellum, Quoy et Gaimard. 
Ihplectella^ Owen. 
Sponge fistulate ; fistula single, elongate, without a massive base. Skeleton : primary 
fasciculi radiating from the base in parallel straight or slightly spiral lines ; secon- 
dary fasciculi at right angles to the primary ones. Oscula congregated, with or 
without a marginal boundary to their area. 
The congregation of the oscula in Alcyoncellum corhicula and A. aspergillum is not a 
character peculiar to those sponges. A similar mode of arrangement exists in several 
species of Geodia. In G. gihberosa^ in the Museum of the Jardin des Plantes at Paris, 
they are congregated in an area with a well-defined boundary, and in specimens of G. 
Barretti in my possession they are situated in deep depressions or cavities on the sur- 
face of the sponges ; and these cavities or areas are not uniform in either shape or size ; 
so we may infer that the presence in some species of Alcyoncellum of a well-defined 
marginal boundary to the oscular area, and its absence in other species, amounts to a 
specific difference rather than to a generic distinction ; but in either case the oscula are 
congregated at the distal extremity of the sponge, and the areas of its parietes are the 
inhalant portions of the animal. The inhalation and exhalation of water is precisely on 
the same principle as that which obtains in Grantia ciliata ; the whole of the parietes 
are appropriated to inhalation, the incurrent streams are passed through the interstitial 
cavities and discharged into a common cloaca, and the effete stream ejected at the distal 
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