the Genus Tragosia, Gray. 173 
of species containing trichodragmata and makes extensive 
use of this form of spicule as a guide to classification. It 
is not necessary to criticize his conclusions in this place, 
except in so far as they concern the genus Tragosia. He 
did not, of course, know that Tragosia infundibuliformis 
contains trichodragmata, or he must have realized that his 
new genus Awvidragma was not required. 
The diagnosis of Awidragma may be quoted in full; it 
runs as follows :—‘‘ Axinellide typically of thin lamellar 
habit, stipitate, with even surface. Skeleton composed of 
primary lines of stylote megascleres, traversing the sponge 
in the direction of its growth, and of secondary lines (con- 
necting-fibres ?) formed of oxea ; there is no special dermal 
skeleton. The megascleres are of the two forms mentioned, 
which are quite distinct in kind. The microscleres are tri- 
chodragmata accompanied or not by single trichites.” This 
genus is proposed for Topsent’s Awinella padina [1896], 
from the Gulf of Lyons, a species which is shown by the 
discovery of trichodragmata in Tragosia infundibuliformis 
to be closely related to, if not identical with, the latter. 
It is quite clear that Hallmann’s genus Aaidragma 
should be abandoned in favour of Tragosia. The synonymy 
of the other Axinelline genera with trichodragmata is too 
difficult and complex a problem to be discussed in this place, 
but the study of these forms will probably be found to 
afford strong support to the view that the “ Axinellide ”’ 
are merely a heterogeneous assemblage of lipochelous Des- 
macidonide [e¢f. Dendy, 19214, B]. 
List or LirERATURE REFERRED TO. 
1866. Been J. 8. A Monograph of the British Spongiads, 
vol. ii. 
. A Monograph of the British Spongiads, vol. iii. 
1876. Canter, H. J. “ Descriptions and Figures of Deep-sea Sponges 
and their Spicules from the Atlantic Ocean, &e.” (Ann: & 
Mag. Nat. Hist. ser. 4, vol. xviii.) 
1877. ——. “ Arctic and Antarctic Sponges, &c.” (Ann. & Mag. Nat. 
Hist. ser. 4, vol. xx.) 
1916. Denpy, A. “Some Factors of Evolution in Sponges.” (Journ. 
QQuekett Microscopical Club, vol. xiii.) 
“The Tetraxonid Sponge-Spicule: a Study in Evolu- 
tion.” (Acta Zoologica, vol. ii.) 
“ Report on the Sigmatotetraxonida collected by H.M.S. 
‘Sealark’ in the Indian Ocean.” (Trans. Linn. Soe., Zool. 
vol. xviii, pt. 1.) 
1828, FieminG, J. A History of British Animals. 
1867, Gray, J. E. “Notes on the Arrangement of Sponges, with the 
Descriptions of some new Genera.” (Proc. Zool. Soc. 1867.) 
1921 B. 
