354 General Notes. 
and says that in Australia almost all of the Tetraxonia have devel- 
oped into the Tethyoid type. He does not agree with Ridley and 
Dendy in their views of the origin of the horn-sponges, but regards 
this group as having a polyphylitic origin. The Australian Calc- 
sponge fauna is very rich, while the deep-sea Hexactinellide and 
Lithistide are wanting. 
His conclusions regarding the sponges are:—(1) The littoral 
sponges are widely distributed, about half the species being cosmo- 
politan ; (2) The most recent and most highly-developed forms 
rarely occur in the colder waters, and their relative numbers is in 
proportion to the coldness of the sea; (3) Newer forms follow the 
older, not only when we go from the deeper to the more littoral 
zones, but from the poles to the tropics; (4) The lower and older 
types are more plenty in the cold than in the warmer seas, and are 
especially rare in Australia; (5) There are a series of forms which 
are confined to Australia, but there is only a few which are confined 
to any other region; (6) All the larger genera are cosmopolitan ; 
(7) The fresh-water sponges are more uniform and more widely- 
distributed than are the marine sponges. 
New Enetanp Mepus%.—Dr. J. W. Fewkes presents (Bulletin 
Mus. Comp. Zool., xiii.) a list of the Medusze which he has studied 
on the coasts of Maine and Grand Menan. The list embraces fif- 
teen species and is illustrated by six plates.. A full account is given 
of Nanomia cara, supplementing the account of Dr. Alexander 
Agassiz, showing that these forms really possess both sexes united 
in one colony, and giving an account of the embryos up to the 
eight-cell stage. The rare Callinema ornata is also figured and 
escribed. The most interesting form mentioned in the paper 1s a 
curious parasitic hydroid, for which a new genus and species (Hy- 
drichthys mirus) is established, which was found at Newport, 
R. I. Attached to the side of a specimen of the fish Seriola zonata 
clearly to be with the former; and the similarities of the form to 
the Siphonophores are scarcely more evident than are those of any 
of the Hydromeduse. 
