206 
ZOOLOGY OF THE FAR EAST. 
colour and consists of groups of gemmules covered by skeleton- spicules. No patch 
is more than 5 mm. long. It is impossible, therefore, to describe the structure of 
the sponge. 
The gemmules are firmly attached to the stone and lie closely adjacent to one 
another ; each is covered by a dome formed of a dense network of single skeleton- 
spicules, the different domes coalescing at the margin. Each gemmule is nearly 
spherical, but the upper surface of most of them has collapsed and become concave. 
In the middle of this surface there is a single curved forminal tubule, which projects 
through the dome of skeleton-spicules. 
The skeleton-spicules are very small and relatively slender, sharply pointed at 
both ends and densely covered with short spines. The gemmule-spicules are minute. 
Their rotules are relatively large and their shafts short. Both rotules are slightly 
Fig. 4. — Spicules of Trochospongilla sol ; macroscleres, x 250 : birotulates, x 780. 
concave and the upper rotule is slightly smaller than the lower one, the shaft 
projects upwards as a nob in the middle of the upper rotule ; the surface of the 
rotules is ornamented by straight radiating striae. 
Measurements : — 
Diameter of gemmule . . . . 0'357 ^n^- 
Length of macrosclere . . . . 0'i62 — 0'3i ,, 
Breadth of macrosclere . . . . • . o'oii ,, 
Length of gemmule-spicule . . ... . . 0 009 „ 
Diameter of lower rotule of gemmule-spicule . . o oii ,, 
Type- specimen. No. ZEV. 7183/7, Zool. Survey of India {Ind. Mus.). 
Locality. Shore of Si Dong Ding I., Tai-Hu, Kiangsu Province, China. 
The sculpture of the gemmule-spicules distinguishes this species from any other 
with which I am acquainted. The dried masses of gemmules were not distinguished 
in the field from similar masses of the gemmules of Spongilla stanleyi with which they 
occurred. 
