REPORT OR THE TETRACTIRELLIDA. 
239 
oxeate; 0 '01 9 mm. in diameter, 5. Somal microstrongyle, cylindrical or fusiform, cen- 
trotylote or not, surface roughened, 0‘0237 by 0’004 mm. 
Colour. — Black externally. 
Habitat. — Quarnero, Adriatic ; Algiers. 
Remarks. — This species is distinguished from Erylus discophorus, 0. Schmidt, by 
the form of the sterraster, and the presence of microstron gyles throughout the choano- 
some. The measurements of the spicules were taken from a type-slide of the Adriatic 
example in the British Museum collection, and confirmed from preparations mounted by 
myself from a specimen presented me by Professor von Graff, The Algerian sponge of 
the same species is represented by a slide in the British Museum ; it is probably correctly 
identified by Schmidt, though the spicules are of somewhat difierent dimensions ; my 
measurements are as follows: — Oxea, I’O byO'016 mm.; dichotrisene, rhabdome 0’46 mm, 
long; proto- and deuterocladi, each 0T08 mm. long; microstrongyle 0’057 by O'OOS mm. 
Erylus carteri, n. sp. 
Stelletta euastrum, Carter, Ann. and Mag. Nat. Hist., ser. 5, vol. vi. p. 489, pi. vii. fig. 41, 1880. 
Sponge. — Lamelliform, thin, incrusting, surface even ; oscules distinct, scattered singly 
or collected in groups. 
Spicides. — I. Megascleres, 1. Oa;ea, 0'85 by 0’028 mm, 2, sometimes 
passing into a dichotrisene ; rhabdome 0'56 by 0‘056 mm. 
II. Microscleres. 3. Sterraster, disciform, elliptical, very thin, actines minutely 
spined at the ends, 0’24 mm. long by 0T27 mm. broad and 0’042 mm, thick. 4. Chiaster, 
0'028 mm. in diameter. 5. Microxea, centrotylote. 
Colour. — Greyish-white. 
HaMtat. — Gulf of Manaar. 
Erylus lendenfeldi, n. sp. 
Stelletta euastrum, Carter, Ann. and Mag. Nat. Hist., ser. 5, vol. vi. p. 490, pi. vii. fig. 42, 1880. 
Sponge. — Ovate; surface even, dimpled; pores 0T6 mnn in diameter, the simple 
openings of chones, generally dispersed ; oscules distinct, of different sizes, irregularly 
distributed. 
Spicules. — I. Megascleres. 1. Oxeaox strongyle,0'^0hj mm. 2. Orthotrisene, 
rhabdome strongylate, 0‘316 by 0'0276 mm.; cladi O' 15 mm. long, 
II, Microscleres, 3. Sterraster, ellipsoidal, depressed, from OTO by 0‘065 to 0T35 
by 0'058 mm. 4. Chiaster, actines few, slender, tylote, sometimes minutely spined, 
0'03 mm. in diameter. 5. Oxy aster, actines usually four in number, minutely over the 
