482 PROF. A. DENDY AND MISS L. M. FREDERICK ON 
eqniaiionlar and more or less equiradiate, but soiiietimes the rays become 
slightly unequal. 
(3) Quadriradiates of three kinds : («) (PI. 26. fig. 2 c), regular, very 
abundaiat, like the small triradiates with the addition of a slender, curved, 
often crooked, apical ray ; the facial rays measure about 0'15 by 0'03.5 mm. : 
(b) (PL 26. fig. 2 d), sagittal, with a wide oral angle and a slender, back- 
wardly directed, very slightly curved apical ray ; the oral rays (which 
measure up to 0"13 by 0'02 mm.) are sometimes slightly curved, the basal 
ray is slightly shorter than the oral and straight and conical ; these spicules 
are not very abundant and are probably confined to the exhalant canals and 
the oscular margin: (c) (PL 26. fig. 2e), sagittal, small, very irregular, 
usually with curved, crooked rays, measuring about 0"1 by 0'019 mm. 
{b) and (c) have only been found in boiled-out preparations. 
(4) Trichoxea (PL 26. fig. 5, tr.) very slender, sharp-pointed, measuring 
about 0'16 mm. in length. 
Register No. and Locality. III. 12, Wooded Isle. 
4. Leucetta chagosbnsis Dendy. 
Leuoetta chayosensis Dendy [191.3]. 
There are two specimens in the collection. One (R.N. II. 4), which measures 
.32 mm. in length, 16 mm. in height, and has an average thickness of 8 mm., 
is compressed and irregular, proliferating into short, nodular processes ; the 
vents, which have slightly prominent margins, are scattered and vary in size 
between 1 and 2 mm. The second specimen (R.N. II. 5 b) consists of three 
small lobose fragments which have been broken off a larger specimen. 
The Abrolhos specimens agree closely with the type except that the 
ectosome is thinner and the subdermal cavities slightlj^ smaller. Numerous 
embryos are present, the structure of which indicates clearly tliat the larva 
of Leucetta is a parenchymula. 
Premously hnown Distribution. Chagos Archipelago, Indian Ocean (Dendi/). 
Register JSfos. and Locality. II. 4, II. 5 b, Wooded Isle. 
5. Leucetta mickoraphis Haeckel. 
Leucetta primigenia var. microraphis Haeokel [1872]. 
Leuoonia dura PoleJaefE [1883]. 
Leucetta primigenia var. microrrhaphis Ridley [1884]. 
Leucetta microrhaphis LendeDfeld [1885]. 
Leucandra microrhaphis Dendy [1892]. 
Leucetta microraphis Dendy & Kow [1913]. 
The single specimen consists of a small, oblong fragment measuring about 
22 by 10 mm. ; at one end there is a small slit-like vent measuring about 
2 by 1 mm. Colour in spirit light brown ; texture very hard and coarse. 
The skeleton consists of triradiate spicules only; these are of two sizes and 
scattered irregularly throughout the sponge except at the surface, where 
