REPORT ON THE TETRACTINELLIDA. 
141 
sometimes the reverse, in the latter case curved, giving the cladome a cyathiform 
appearance, in the former usually straight ; deuterocladi sometimes extending horizon- 
tally, sometimes projecting slightly forwards. Rhabdome 4'418 to 5'7, by 0’09 to 0‘11 
mm., protocladi 0'143 to 0'16 mm. long, deuterocladi 0'19 to 0'48 mm. long, chord 
0'524 to 1'114 mm.; distance from the cladal origin to the dichotomy of the arms 
measured along an imaginary line representing the axis of the rhabdome produced 0'095 
to 0'16 mm. 
3. Anatrisene (PI. XIII. figs. 4, 21 ; PI. XV. fig. 25), a conical rhabdome sharply 
pointed or rounded off near the end ; cladi gently recurving from their origin back- 
wards, or first projecting outwards and then recurving ; cladome rounded or flattened in 
front. Rhabdome 3'0 to 4'3 by 0‘032 to 0'039 mm., cladi 0’127 to 0‘16 mm. long, 
chord 0'16 to 0‘2 mm., sagitta 012 to 015 mm. 
II. Microscleres. 4. Anthaster (PI. XIII. figs. 5, 22-24 ; PL XV. fig. 26), centrum 
usually not enlarged ; actines cylindrical or sometimes conical, minutely spined, either 
entirely, or partially, in the latter case free from spines near the origin ; usually from 
three to seven in number, sometimes numerous; from 0'021 to 0'028 mm. long. 
5. Chiaster (PI. XIII. figs. 6, 25-28 ; PI. XV. fig. 27), centrum usually not enlarged, 
but occasionaUy, though very rarely, forming a sphere of greater diameter than the 
length of the actines ; actines slender, hair-like, usually smooth and tylote, sometimes 
thickened and roughened; sometimes ending abruptly, without becoming tylote; usually 
numerous ; 0’006 to0’008 mm. long. 
Colour. — Greyish or cream-coloured white ; in one group of specimens russet-red. 
Habitat. — Station 162, off East Moncceur Island, Bass Strait, April 2, 1874 ; lat. 39° 
10' 30" S., long. 146° 37' 0" E. ; depth, 38 fathoms ; bottom, sand and shells. Dredged. 
Station 163a, off Twofold Bay, Australia, April 4, 1874; lat. 36° 59' S., long. 150° 
20' E. ; depth, 150 fathoms; bottom, green mud. Dredged. 
Port Jackson, June 3, 1874 ; depth, 6 to 15 fathoms. 
Remarks. — A large number of specimens of this sponge were dredged. From 
Station 162 three specimens, from Station 163a thirty-five specimens, and from 
Port Jackson eleven specimens were obtained. After examining a few specimens 
from each station, I was inclined to regard those from different stations as 
belonging to three different species, the first distinguished by its reddish , colour 
and minute difference in the chiasters ; the second distinguished from the first by 
containing typical chiasters, and from the third by the straightness of the protocladi of 
the dichotrisene ; and the third characterised by the curved form of the protocladi. On 
further examination, the characters of the spicules appeared to be subject to much 
variation, and I therefore made an examination of the spicules of nearly thirty specimens ; 
the result showed that none of the differences observed in the spicular forms could be 
