Notes on some Sponges. Bg Mr. J. Yate Johnson. 463 
cylindrical smooth loosely spiral rods of two or three turns, with the 
ends blunt or rounded. These are abundant. 
N ISELLA. g. n. 
Spicules of two forms, viz. a slender shaft with six long rays at 
the middle, and a fusiform shaft with two whorls of three short rays 
at the middle. 
Nisella verticillata sp. n., plate YI. fig. 6. 
A specimen of the alcyonarian coral Pleurocorallium johnsoni 
(Gray) had the solid stony stem broken away from the base, and the 
fracture crossed several small cavities, unconnected with each other. 
Out of these were picked fragments of a dark brown sponge of close 
texture with the spicules placed irregularly in all directions. When 
treated with nitric acid it yielded two interesting forms of spicule. 
The most abundant is normally a slender straight shaft, from the 
middle of which radiate six equally slender arms, which are half as 
long as the shaft, so that the whole forms an eight-rayed star. The 
arms and the two halves of the shaft taper slightly, and the ends are 
knobbed. There is, however, a good deal of irregularity in the position 
of the arms. Sometimes they are arranged in a spiral manner, and 
sometimes there are two whorls of three rays each. The second form 
of spicule is a fusiform shaft with two whorls of three short rays each 
at the middle. The shaft is roughened or finely ringed, and its ends 
as well as the ends of the rays are knobbed. The latter form of spicule 
connects this species of sponge with Carter’s Alectona Millari * in 
which a fusiform spicule is found with two rings, each of three tubercles 
at the middle in place of two whorls of rays, along with acerate spicules. 
In a small dark brown sponge, picked out of cavities in the stem 
of another coral ( Bendrophyllia ramea) not only were the two forms 
above described abundant, but a third form of spicule was sparingly 
present, viz. a slightly curved fusiformi-acerate shaft more than twice 
as long as No. 2 with an annular swelling at the middle. This may 
have been an intruder. 
The soft parts of Nisella verticillata seem under some circum- 
stances to be transformed into a hard structureless homogeneous cake 
of a dark brown colour. Such a cake is compact enough to crack across 
when drying after immersion in water. Imbedded quite irregularly 
in one mass of this kind, not only the forms of spicule Nos. 1 and 2 
above described were found, but also (a) numerous slender forcipes, 
( b ) stout spinulose spikes tapering from the truncate end to the other, 
(<?) bihamate C-shaped, with simple acute ends, ( d ) smaller two- 
pronged bihamate or equi-anchorate. All these must be considered 
as belonging to other sponges. 
* Jouru. R. Micr. Soc., ii (1879) p. 497, pi. xvii. 
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