and Nomenclature of Sponges. 165 
the Coral Sponges would be placed near the Euplectellade, 
thus :— 
Section I. MaLacospor&. Soft-spored Sponges. 
Subsection I. Lerosponcia. Spicules none, or, when pre- 
sent, of only one kind. 
Order I. Keratosponci# (Horny Sponges), including 
the families Spongiade &e. 
Order II. RapHisponcta# (Needle Sponges)—that is, the 
order Leiospongie of my Table, including Halichon- 
driade &e. 
Subsection II. AcANTHOSPONGI&. Spicules always pre- 
sent, of more than one form, akin in-each Sponge. 
Order ITI. Coratiiospone1a (Coral Sponges). Spicules 
anchylosed by siliceous matter, as Dactylocalycide, 
Aphrocallistide, Euplectellade. 
Order IV. ARMATOSPONGIZ (Armed Sponges). Spicules 
distinct, more or less immersed in horny or fleshy mat- 
ter. Includes Esperiade and Tethyade. 
Subsection III. ARENOSPONGLE, or Sand Sponges, &c. 
_ Dr. Bowerbank has complained to me that I have erro- 
neously described the Coralliospongie as formed of “ siliceous 
spicules anchylosed together by siliceous matter, forming a 
netted mass.” He says that I have confounded fibre with 
spicule. As the siliceous spicules are of the same structure, 
whether they are short and thick, or very long cylindrical 
filaments like those of Huplectella, I can see no reason why 
they should not all be called spicules. 
. Bowerbank states that fibres always anastomose and 
form a network, spicules never do so. According to this rule, 
some of the s celia of the Huplectella do anchylose and some 
do not; so that some should be called spicules and others 
fibres. Perhaps this is why Dr. Bowerbank speaks of the 
“long siliceous spicula or fibres of Huplectella” (Brit. Spong. 
1. p. 9). 
| Resco Dr. Bowerbank characterizes the Coral Sponges as 
having a siliceo-fibrous skeleton (B. S. i. p. 203); and he re- 
marks that the structure and mode of growth in this suborder 
of siliceo-fibrous Sponges “ appears to be precisely the same as 
that of the cerato-fibrous sponges ’”’ (zbid.). 
This is true to a certain extent, as the spicules of the sili- 
ceous and the fibres of the horny sponges are each secreted by 
the animal and deposited in successive layers, and merely 
differ in the quantity of animal or horny and of siliceous mat- 
ter that they contain. Some spicules are almost all silica, 
with scarcely any horny matter, and some horny fibres almost 
