SPONGXIDA. 611 



finely hispid surface and the low irregularly lobate form, together 

 •with the spicular characters, they agree dosely with the Australian 

 specimen, but the average diapieter of the lobes is somewhat less 

 (about 10 mUlim.). 



Hah. Providence Reef, Mascarene Islands, 24 fiais. 



Distribution. Port Darwin. 



33. Esperia gelatinosa. (Plate LIV. figs. /-/"".) 



Low incrusting masses, frequently involving foreign bodies, 

 occasionally rising into slender lobes. ' Surface in spirit undulating, 

 glabrous. Consistence tough, elastic, firm. Colour pale greenish 

 grey or pinkish brown ; general appearance gelatiaous, semi-trans- 

 parent. 



Main skeleton rather confused in the incrusting specimens ; the 

 vertical Hnes near the surface being short, broad, loose, and 

 closely approximated ; in thicker specimens the ordinary Esperian 

 distinct spiculo-flbres appear at some distance below the surface ; 

 primaries crossed by more or less numerous detached skeleton- 

 spioules. Dermal skeleton composed of confusedly intercrossing 

 spicules not arranged into spioulo-fi.brous reticulation. Sarcode very 

 pale yellow, transparent. 



Spicules : — (1) Skeleton subspinidate ; head oval, slightly but 

 distinctly demarcated from shaft, about two thirds the maximum 

 diameter of the latter ; shaft tapering rather abruptly to sharp 

 point ; size of spicule -5 by •016 miUim. (2) Large inequianchorate ; 

 large end moderately broad, about half the total length of the spicule, 

 tubercle long, lower angles of outer palms slightly rounded ; small 

 end subtriangular, rather small, pointed below, tubercle small, 

 tongue-shaped, a small reverted margin extending as far as the 

 tubercle in the middle ; size of spicule -OQ by -00^ miUim. (3) Small 

 inequianchorate, large end about three fifths the total length of 

 the spicule; shaft and arms well but gradually curved, tubercle 

 short ; lesser end very small, not prolonged below into a point; length 

 of spicule -019 millim. (4) Bihamate, contort, slender, well curved, 

 sharp-pointed ; size -057 by "002 millim. (5) Trichites in oblong 

 compact bundles about '02 millim. long and "0063 to '0075 millim. 

 in diameter ; spicules approximately straight. Extremely abundant. 



Hah. Providence Eeef and Providence Island, Mascarene group, 

 19-24 fins. ; bottom, sand or dead coral. 



The longest lobes are 20-30 mUlim. long and 3-6 millim. in 

 diameter. In habit, spiculation, and arrangement of skeleton it 

 much resembles E.lmvis, Carter (Ann. & Mag. N. H. 1882, ix. p. 291, 

 pi. xi. fig. 16), from Venezuela, and E.peUucida, mihi (Part I., p. 437, 

 of this Eeport) ; but the small inequianchorate here has not the 

 terminal point described by Carter, and the trichites are much 

 smaller ('02 millim. instead of "067 nuUim. long) ; from E.pellueida 

 it differs in the small, short, quadrangular trichite-bundles, in the 

 smaller size of the anchorates, &c. The species is quite abundant, 

 though no large specimens were foimd. 



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