REPORT ON THE TETRACTINELLIDA. 
17 
abundantly present in tlie neighbourhood of the flagellated chambers, where it is finely 
granular. Flagellated chambers 0'04 mm. in diameter. 
Spicules. — I. Megascleres. 1. Oxea, anisoactinate, fusiform, more finely pointed at 
the proximal than at the distal end ; 2 '5 by 0’031 mm. 
2. Protrisene, a conical rhabdome, tapering to a filiform termination ; cladi two 
nearly equal in length, but shorter than the third; rhabdome 2‘32 by O’Ol mm.; cladi — 
longer 0'14 mm., shorter 0'067 mm. in length. 
3. TricTiodal protrisene of the usual form, very diminutive. 
4. Anatrisene, a conical rhabdome, tapering from the cladome to a filiform termina- 
tion ; 2'856 by 0‘0135 mm.; cladi 0'075 mm. long, chord 0*075 mm., the axial fibre of 
the rhabdome extends 0*008 distally beyond the origin of the axial fibres of the cladi, 
the cladal end of the rhabdome correspondingly projects in a rounded process in front. 
II. Microsclere. 5. Sigmaspire of the usual form, 0.*012 mm. long. 
Colour. — White, of a faintly grey tint. 
Habitat . — Station 236, off Japan, June 5, 1875 ; lat. 34° 58' N., long. 139° 29' E.; 
depth, 775 fathoms; bottom, green mud; bottom temperature, 37°*6 F. 
Remarks . — There is but a single small specimen of this sponge ; it measures about 
7 mm. in height and 6 mm. in breadth ; it is probably a very young form, and, as it 
does not offer any unusual or particularly distinctive character, I refrain from giving it 
a name. 
The characters of the oscules and pores I could not determine. 
Chrotella,^ n. gen. 
The ectosome is a cortex, excavated by subdermal cavities, and furnished with 
tangentially disposed spicules. 
Chrotella simplex, Sollas (PI. II. figs. 1-4). 
Chrotella simplex, Sollas, Prelim. Account, Sci. Proc. Roy. Dubl. Soc., vol. v. p. 181, 1886. 
Sponge ellipsoidal or subspherical, free, surface uniformly pilose, conules absent. 
Oscules small, one or more in number. Pores in sieve-like areas overlying the subdermal 
cavities. 
Spicules. — I. Megascleres. 1. Oxea, fusiform, almost isoactinate ; 2*8 to 3*0 mm. by 
0*0217 to 0*0237 mm. 
2. Protrisene (PI. II. fig. 3). Ehabdome cylindrical, tapering to a filiform termina- 
tion ; cladi conical, widely extended; rhabdome 3*4 by 0*02 mm.; cladi 0*158 by 
0*016 mm. 
* the skin. 
(ZOOL. CHALL. EXP. — PART LXIII. — 1887.) 
Err 3 
