134 BULLETIN OF THE BUREAU OF FISHERIES. 
pose, might be brought to the laboratory, or certain breeding experiments might be 
begun on shipboard, and the cultures handled in the laboratory later. 
The scheme of classification followed is, in general, that used by Dendy in 1905. 
Some alterations which seem to be advisable have been made. In the scheme as here 
adopted the larger groups of the noncalcareous sponges are as follows: 
Order 1. Myxosponcipa.—Simple forms without askeleton. Absence of the skeleton primitive (Halis- 
arca, Bajalus, Hexadella, Oscarella). 
Order 2. HeEXACTINELLIDA (Triaxonida).—With triaxonid, characteristically hexactinellid, siliceous 
spicules. 
Order 3. TeTRAxonIDA.—The characteristic form of spicule is a siliceous four-rayed sclerite, each ray 
representing a particular axis (tetraxonid or tetractinellid spicule). But in some groups these 
spicules have been lost. 
Suborder 1. HomoscLEROPHORA (Dendy, 1905).—Megascleres and microscleres are not yet sharply 
differentiated from one another (Plakinide, Corticide, Thrombidz). 
Suborder 2. ASTROTETRAXONIDA (Hentschel, 1909).—Tetraxonid sponges without desmas, char- 
acterized fundamentally by the astrose microscleres, which, however, have been lost in 
the evolution of some groups. 
Tribe 1. ASTROPHORA (Sollas, 1888).—With tetraxonid megascleres and astrose microscleres. 
Tribe 2. ASTROMONAXONELLIDA (Dendy, 1905).—Sponge body generally compact and mas- 
sive, sometimes approaching a definite shape, but also incrusting. Megascleres all mon- 
axonid, often radially, or somewhat radially, arranged. Skeleton rarely fibrous, not dis- 
tinctly reticulate, and usually without spongin. Microscleres, if present, are asters of 
*some form or other. Presumably derived from the Astrophora through loss of tetraxonid 
megascleres. Equivalent to Hadromerina, Topsent. 
Suborder 3. SIGMATOTETRAXONIDA (Hentschel, t1grr).—Tetraxonid sponges without desmas, 
characterized fundamentally by microscleres which are either sigmata or forms derivable 
from the sigma. But the microscleres have been lost in some groups. 
‘Tribe 1. SIGMATOPHORA (Sollas, 1888)—With tetraxonid megascleres. Microscleres when 
present are sigmata. 
Tribe 2. SIGMATOMONAXONELLIDA (Dendy, 1905).—Megascleres all monaxonid. Skeleton 
very commonly reticulate or fibrous, with a good deal of spongin. Microscleres, when 
present, either sigmata or derived forms such as chelz. ‘True astrose microscleres are 
absent, except, possibly, in an aberrant species or two. Presumably derived from the 
Sigmatophora through loss of the tetraxonid megascleres. Equivalent to Halichrondrina 
auct. 
Suborder 4. Lirarstipa.—Tetraxonida with desmas. 
Order 4. Krratosa (Euceratosa, Dendy, 1905).—Skeleton made up of horny fibers. Without proper 
spicules. Absence of spicules primitive and not due to evolution by loss. Sand grains and other 
foreign mineral particles often aid in forming the skeleton, and in exceptional cases constitute its 
chief part. 
The families, subfamilies, and genera represented are defined in the text. In 
constructing these and the above definitions we have freely used the memoirs of Dendy, 
Lendenfeld, Lundbeck, Sollas, Topsent, and Vosmaer. A consideration of some com- 
parative data, falling for the most part under the head of variation, together with a 
discussion of the facts on which the genera are made and classified, has considerably 
lengthened the sections assigned to several of the species. This matter follows, in each 
section, the description of the species, from which it is more or less conspicuously set off. 
