REPOBT ON THE TETKACTINELLIDA. 
299 
times the cladi may be seen applying themselves to the whole length of the epactine of 
an adjacent desma. The syzygial tubercles expand and adapt themselves to the attached 
surface in the usual fashion (PL XXXI. fig. 6b). 
Genus Neosiphonia, n. gen. 
Jereopsis, 0. Schmidt, Spong. Meerb. Mexico, p. 20, 1879. 
Tetracladidge with a rounded body, supported on a longer or shorter stem ; canal- 
system as in the fossil genus Siphonia or Jerea. The ectosomal megascleres are dicho- 
or tricho-trisenes. The microsclere is a spiraster. 
Schmidt states that ectosomal megascleres are absent in the specimens he examined, 
but he does not add whether these were fresh or deciduous examples. A fragment sent 
me by Professor Agassiz is certainly deciduous. If Schmidt’s statement should be con- 
firmed as true of fresh specimens, it would necessitate alterations in our classification ; 
but since dichotrisenes are associated with the species from Fiji, one would be surprised 
if they should prove to be absent in that from the Gulf of Mexico. 
Neosiphonia superstes, n. sp. (PI. XXXI. figs. 7-12). 
Sponge (PI. XXXI. figs. 7, 7a, 76). — A somewhat spherical body, produced below 
into a short, stout, compressed pedicel, which ends without expanding into a base for 
attachment. Oscules collected in a somewhat depressed area on the summit, the patent 
ends of the excurrent canals, which descend into the sponge perpendicularly along the 
axis, but in a direction more and more parallel to the surface as they lie nearer to 
it. Pores (?). Small, circular holes scattered thickly over the outer surface of the 
sponge, including the pedicel, are the open ends of the incurrent canals, which are 
smaller than the excurrent, and enter the sponge perpendicularly to the surface, pro- 
ceeding towards the centre along radial lines. 
Spicules . — I. Megascleres. 1. Desma (PI. XXXI. figs. 11, 11a). The four epac- 
tines, about OTO to 0'20 by 0‘07 mm., bifurcate into cladi, some or all of which 
again subdivide once or oftener into smaller, irregular, twig-like branches. These end in 
syzygial tubercles, which apply themselves to the cladi or tubercles of adjacent desma, 
and unite with them by clasping and intergrowth in the usual manner (PI. XXXI. 
figs. 12, 12a). Small cladi ending in tubercles are given off from the surface of the 
desma generally, except from the epactines, which are devoid of accessory processes as 
far at least as the extension of the axial fibre. The axial fibre extends from the centre 
through the epactines for a distance varying from about 0'065 to 0T6 mm., sometimes, 
but rarely, extending as far as the point of bifurcation, though in one or two instances 
it has been traced a little beyond it, bifurcating with the epactine, and extending as a 
