bo 
PERCY SLADEN TRUST EXPEDITION 
As might be expected from the locality a large proportion of the species are 
apparently new, though some of these are very closely related to already known forms. 
Of the six old species, Lewcascus simplex has previously been obtained in Australian 
and New Zealand waters; Pericharax heteroraphis at Tristan da Cunha in the South 
Atlantic ; Leucaltis clathria from the Amirantes, Ceylon, E. Africa, Australia, Florida, the 
Bermudas and Portugal; Lewcandra echinata from the Amirantes and Mauritius, and 
probably Australia; Leucandra wasinensis from the East Coast of Africa, and Grantessa 
hastifera from the Red Sea. 
The classification adopted in this paper is that elaborated by myself and my colleague, 
Mr R. W. H. Row, in a systematic and phylogenetic revision of the Calearea which we 
hope to publish shortly. The appearance of the memoir in question will, I hope, render 
it unnecessary for me to discuss questions of taxonomy and phylogeny on the present 
occasion, and I content myself with giving diagnoses of the families and genera represented 
in the collection. 
Family Homoccelide Dendy and Row MS. 
The whole of the gastral cavity and its various outgrowths lined by collared cells 
throughout the life of the sponge. Sponge colony rarely radiate, and if so the 
central individual retains the primitive ascon structure with a lining of collared cells and 
without a special gastral cortex. No subgastral sagittal radiates. No true dermal 
membrane or true dermal cortex. 
Genus LeucosotentaA Bowerbank (emend.). 
Diverticula of the gastral cavity, if any, never radially arranged around a central 
tube. Skeleton composed of triradiate or quadriradiate spicules, to which oxea may be 
added. No uteoid dermal skeleton ever present. Nuclei of collared cells basal or apical. 
Section B. 
Without oxea. Sponge colony typically forming a reticulation of simple ascon- 
tubes. 
1. Leucosolena gardineri un. sp. 
(Plate 1, figs. 1, 2; Plate 3, figs. 1, 2, 3.) 
This species is represented in the collection by two specimens, which, although 
coming from the same locality, differ considerably from one another in appearance. This 
difference, however, may be partly (though not entirely) accounted for by a difference in 
the condition of the specimens*, the one (cxx. 7; Plate 1, fig. 1) being expanded and 
having more or less conspicuous and widely open vents, while in the other (cxx. 11; 
Plate 1, fig. 2) the vents are difficult to recognize and almost if not completely closed. 
Moreover the latter specimen is full of large maturing ova, and the mesoglcea is densely 
* Cf. Minchin [1892]. 
