EEPORT ON THE TETRACTINELLIDA. 
261 
mm. 5. Chiaster, centrum well developed, actines cylindrical, tylote, varying from 
about six to twelve in number, 0'016 mm. in diameter. 
Colour. — Externally brown, yellowish within. 
Habitat. — Samoa Islands. 
Remarhs. — I owe a type-slide containing mounted spicules of this sponge to the 
kindness of Dr. Perceval Wright, to whom it was presented by Selenka. The spicules 
evidently belong to a sponge closely related to Cydonium eosaster, Sollas, and 
Cydonium globostelliferum (Carter). The spheraster is, howe\^er, much larger than in 
either of these species, and the rhabdi are strongyles, not oxeas. The minute aster, 
which I have termed a chiaster, should perhaps in strictness be termed a spheraster with 
tylote actines. 
Cydonium globostelliferum (Carter). 
Geodia glohostellifera, Carter, Ann. and Mag. Nat. Hist., ser. v. vol. vi. p. 134, pi. vi. fig. 38, 
1880. 
? Geodia glohostelUfera, Ridley, Spong. “Alert,” p. 480, pi. xliii. fig. 6, 1884. 
Sponge. — Globular, free or attached ; surface covered with attached detritus. 
Spicules. — I. Megascleres. 1. Somal oxea, 2'39 by 0'021 mm. (C.), 3'0 by 0'038 
mm. (E.). 2. Cortical oxea, 0T6 by 0‘005 mm. (R., not mentioned by Carter). 3. 
Orthotrixne, rhabdome l‘7l by 0‘021 mm. (C.), by 0'07 mm. (R.) ; cladi, chord 0‘5 mm. 
(C.), 0'58 mm. (R.). 4. Protrixne, cladi 0T12 mm. long (C.), 1 mm. (R.). 
II. Microscleres. 5. Sterraster, 0’07 mm. (C.), 0'09 mm. (R.), in diameter. 6. 
Spheraster, 0'0211 mm. (C.), 0'028 mm. (R.), in diameter. 7. Somal chiaster, actines 
numerous, truncate, 0'0042 mm. (C.), 0'0063 mm. (R.), in diameter. 8. Choanosomal 
chiaster, 0'034 mm. (C.), 0’038 mm. (R.), in diameter. 
Colour. — Violet-grey (C.), pale crimson in places (R.). Size, 19 mm. (C.), 80 mm. 
(R.), in diameter. 
Habitat. — Gulf ofManaar (C.) ; Port Darwin, north-east coast of Australia, near tide 
marks, bottom, sand and rocks (R.). 
Remarhs. — The letters (C.) and (R.) placed after the measurements indicate that they 
are quoted from Carter and Ridley respectively. It will be seen that the two sets of 
measurements correspond fairly well, and probably the two sponges belong to the same 
species, as Ridley supposes ; there still remain two points for further examination before 
this can be regarded as certain, — first the apparent absence of cortical oxeas in Carter’s 
sponge, and next the small diameter of the orthotrisene as compared with that in Ridley’s 
specimens. 
The species is evidently very similar to Cydonium eosaster, in which, however, 
dichotrisenes and not orthotrisenes are present. 
