! 105 1 
According to the chemical nature of the skeleton and the 
?.hape of the spicules, if present, the sub-kingdom of the 
Sponges may be grouped into the following six classes which, 
however, are not of equal values: 
1. Myxosp&ngiac ; Without a skeleton. 
2. CercUesa i Horny Sponges. 
3. MonaxOHida ; Siliceous Sponges* with one-rayed spi- 
cules. 
4. TetractineUida : Siliceous Sponges, with four-rayed 
spicules. 
5. HcxaciiHelUda: Siliceous Sponges, with six-rayed 
spicules, 
6. Cakarea : Calcareous Sponges. 
The two varieties of Neptune*s Cup {Poterion neptuni), 
shown on pi. XXI, belong to the Monaxonida. They occur in 
water of moderate depth and were yellowish grey in colour 
when alive. They are about 5 feet 6 inches in height. But on 
the local coral reefs Monaxonida of many different shapes are 
found, branching, fan-like, spherical, encrusting, and of ali 
imaginable tints, yellow, grey, crimson, blue, green and black. 
Two specially beautiful specimens should be mentioned, both 
from Telegraph cables and presented by Mr. Ladds, viz. a 
Chalimi, with large branching tubes, and an Echinodtctyum, 
farmed of a wide mesh work, fan-!ike spread out in one plane. 
The only known Freshwater Sponges {SpmigUlkiae) also belong 
to this group. They are practically cosmopolitan and occur 
also in India and the northern parts of the Malay Peninsula, 
but have not yet been recorded from the southern parts. 
The TeiractiiielUdd are generally of a compact or spheri- 
cal shape and of sob r colouring, greyish or yellowish. 
The HexactiHeUidtt occur only in great depths. The best 
known of them is the Venus Flow^er Basket {EupkcteUa tisper- 
gdiitm). The exhibited specimens are merely the skeletons, the 
soft parts having lieen removed by maceration. Here the 
spicules are of great size and form thick glass-like strands or 
fibres. Some specimens, from the China Sea, from a depth of 
115 fathoms, were given by Mr. Ladds, and others, from Cebu. 
said to have come from a depth of 42 feet only, by Da to Mentri 
Besar of Johore. 
Tlie Calcareous Sponges are white or light yellowish in 
colour. They attain their greatest development in the arctic 
seas. The Ujcal forms are few and small, mostly in the shape 
of little tubes, less than an inch in length. 
