1915.] N. ANNANDALE: Indian Boring Sponges. 2S 
notice they apparently escaped, in his account of the sponges of the 
Mergui Archipelago: Fauna of the Mergui ArchipelagolI, p. 75. It 
is remarkable in the form of its nodular amphiasters, the “‘ no- 
dules’’ of which are reduced to short, slender, blunt or pointed 
branches totally devoid of spines. Reduced spirasters of the type 
common in the genus are also present, while the macroscleres are 
smooth amphioxi. 
General structure.—Nothing is known of the general structure 
except that the sponge consists, in part at any rate, of slender 
apparently cylindrical branches ramifying in dead coral. 
Papillae.—The papillae, of which several imperfect examples 
were extracted, are evidently very small, probably not more than 
03 mm. in diameter. They are protected by dense masses of up- 
right macroscleres. 
Spicules.—The macroscleres are small, slender, smooth, sharply 
pointed, spindle-shaped amphioxi; a large proportion of them are 
definitely geniculate in the middle. The average length is 0°08 
mm. and the average breadth in the middle 0-003 mm. 
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3 f ee, LA 4 
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Fic. 4.—Spicules of Thoosa laeviaster. 
Only two types of microscleres can be distinguished; (a) 
smooth, rather slender amphiasters surrounded at some little dis- 
tance from each extremity by a circle of several (normally 4) 
horizontal branches, which are also smooth and relatively slender. 
These are usually blunt but sometimes pointed: they are always 
stouter at the base than at the tips. ‘The length of each branch 
is usually equal to the distance of its base from the nearest ex- 
tremity of the shaft, which terminates in the same manner as the 
branches, and the distance apart of the two circles is considerably 
greater. The average length of the spicule of this type is from 
about 07041 to 0:08 mm.; the average thickness of the shaft from 
about 0°0065 to o’0r3 mm. and the breadth from tip to tip across 
the branches from 0'0246 to 00328 mm., but all these measure- 
ments are variable. (b) The second type of microsclere is a re- 
duced oxyaster consisting of a pair of relatively long and slender 
curved horn-like spines attached close together to a minute 
centrum. 
Skeleton.—From the fragment of sponge extracted from the 
coral it is evident that the macroscleres are arranged much as in 
