378 Mr. T. Higgin on a new Hexactinellid 
on the head of the chisel, the handle being represented 
by a twisted rope-like anchoring appendage. ‘The colour is 
light sponge-yellow. The dermal surface, now entire only 
on the lower half of the sponge, consists of a latticework, 
generally of a light grey colour, following the gentle undu- 
lations of the exterior of the mass, and is entirely “ pore- 
area.” There are no “vent-ridges” as in Meyerina clave- 
formis; but at the top of the sponge is an irregular funnel- 
shaped cloacal orifice communicating with cavities in the 
centre of the mass. The glass-rope-like anchoring appen- 
dage has been imbedded for half its length in the sandy 
bottom of the sea, has a strong spiral twist, issues from the 
sponge as a cord, and, cord-like, passes up through fully two 
thirds of the head. The latticework of the surface is covered 
by a sarcodic investing membrane, pierced with pores over 
the interstices, which -pores are bordered by the arms of a little 
dermal spicule (to be more particularly described hereafter) 
whose points touch each other, thus forming a lesser lattice- 
work within the interstices of the larger one. The pores thus 
situated lead at once into the general canal-system, which 
consists of very large and small passages, usually with rather 
thin walls, and having an areolar appearance. Some of the 
large canals take a vertical course towards the depression at 
the top of the sponge; others run directly across 1t into the 
central cavities; but all communicate directly or indirectly 
with these cavities—which are more or less ovate in form, and 
extend up and down the sponge round the cord or fixed end 
of the anchoring rope. 
The spicules composing the glass rope are of one kind only, 
12 to 14 inches long, and fusiform. The fixed end of this spicule 
or that part within the sponge, is smooth ; and the surface of 
the free portion is also smooth for half or two thirds of its upper 
part ; but after this it begins gradually to present what appears 
to be a broken spiral line, which by degrees becomes wider. 
Soon the line becomes a ledge, the perpendicular margin of 
which looks towards the sponge; and on the ledges are found 
thin pointed flat spmes or teeth standing up side by side 
in a row or line. By degrees the ledges carrying many teeth 
subside into brackets carrying a single spine only, when 
the spicule has an undulating or sinuous appearance for a 
short distance and finally a short, smooth, straight portion, 
when, having reached its greatest amount of attenuation (viz. 
about 1-400th of an inch in diameter), it again gradually swells 
out to 1-300th of an inch, and then ends in a small, thick, 
conical or mitre-shaped head, with four short round arms, 
recurved and opposite or at right angles to each other, the 
