419 
Bibliographical Notice . 
siliceous sponges of the order Cornacuspongim, Yosmaer, and these 
are placed in the artificial order Monoceratina, characterized by a 
soft ground-substance or mesoderm, with a supporting skeleton of 
spongin fibres, without proper spicules, but in some instances with 
flesh-spicules (microsclera), and with pyriform or sac-shaped ciliated 
chambers ; in other words, they are siliceous Cornacuspongiae, but 
without skeletal or proper spicules in the supporting skeleton, 
though in some instances still retaining minute flesh-spicules of 
the same types as in the more typical siliceous sponges. The fourth 
main group of horny sponges is a relatively small one ; and it is 
considered as a natural order, allied to the siliceous Hexactinellida, 
and from this it is named Hexaceratina. 
The first family of the artificial order Monoceratina, the Aulenidae, 
includes but two genera, Aulena and Hyattella , and in the former 
of these the skeletal fibres are not only charged with sand-grains, so 
common in the fibres of horny sponges, but they possess true echi- 
nating siliceous spicules similar to those of the siliceous Desmaci- 
donidae ; and the author acknowledges that the genusps placed with 
horny sponges not because it properly belongs to this group, but 
because it furnishes an interesting and important link between the 
typical homy sponges and typical siliceous Desmacidonidae. 
The second family of the Monoceratina, the Spongida, is the 
largest of the three groups, and, as defined by the author, contains 
seventeen genera. The sponges of this family are not clathriform ; 
they have small spherical or pear-shaped ciliated chambers, *02 to 
*05 millim. wide ; the ground-substance or mesoderm is granular 
in varying degrees, and the horny fibres of the reticulating skeleton 
may be solid or pithed, and, of course, destitute of proper spicules. 
These sponges are regarded as very closely related to the siliceous 
Chalinids, and in fact merely their modified descendants, which have 
lost the ancestral spicules whilst retaining their external form and 
appearance for a protective purpose. It is significant to find that 
the mere relation of the size of the ciliated chambers is adopted by 
the author as a distinguishing feature, and in certain genera also 
the dimensions of the fibres and the skeletal meshwork are regarded 
as good generic characters. 
Within this family are embraced the sponges of commerce, 
belonging to the genera Euspongia, Bronn, and Hippospongia , 
Schulze. These genera are very closely allied and connected by 
numerous transitional forms which run into each other at every 
point, so that it is an almost impossible task to establish satisfactory 
species or varieties ; but in spite of this the author finds it necessary 
to make nine new forms in Euspongia , bringing the number in this 
genus to thirty-one, and six new in Hippospongia , which now 
numbers twenty- seven species and varieties. 
A full account is given of the peculiar filamentous bodies so 
abundant in the genus Hircinia , which have been the subject of very 
varied opinions amongst spongologists, some considering them to be 
parasitic organisms, others that they have been produced by the 
sponge itself. Lendenfeld formerly held that they were foreign 
organisms, Oscillarians, which multiplied in the sponge and became 
