520 ZOOPHYTA. SPONGIAMI. Halichondria. 



Hemispherical ; one or two inches in diameter ; attached by a flat, soft 

 base ; pale green, with a tinge of* yellow ; when fresh, it exhales an offensive 

 ammoniacal odour ; the surface is nearly smooth, but by drying it becomes 

 villous, and when worn a little, muricate by the extremities of the bundles 

 of fibres ; the fibres decrease in size from the circumference ; the spicula are 

 long, of unequal lengths, fusiform, and where they reach the centre they are 

 extremely fine, forming a dense, villous nucleus ; the animal matter separa- 

 ting the fibres is small in quantity ; from the arrangement of the fibres a 

 horizontal section may be easily made, while a vertical one cannot be effect- 

 ed without difficulty. 



92. T. sphcBrica. — Surface thickly covered with tubercles 

 destitute of hairs. 



Donatio Mer Adriat. G2, t. x. f. 1 — Alcyonium Lyncurium, Linn. Syst. 

 i. 1295 — Spongia verrucosa, Mont. Wem. Mem. ii. 117, t. xiii. f. 4, 

 6. — Coast of Devon. 



Diameter about an inch and a quarter ; " globose, of a yellowish colour, 

 extremely verrucose, and fleshy, which becomes very hard by drying, and is 

 of considerable gravity even in that state ; the warts on the surface are ap- 

 proximating, irregular in shape, and destitute of any pore ; the internal part 

 or nucleus is composed of fasciculate fibres, connected by the animal gluten ; 

 these fill the Avhole internal cavity, and radiate to the centre, appearing like 

 threads of asbestus." — Mont. 



Gen. XLIII. HALICHONDRIA (x«a< ? silcx, andxov^os car- 

 tilago). — Porous, the cartilaginous skeleton strengthened 

 by siliceous spicula; form various. 



* Inhabiting the Sea. 



93. H. papillaris. — Encrusting; orifices large, subtubular, 

 with entire smooth margins ; pores villous ; the spicula fusi- 

 form, slightly curved. 



Spongia informis durior, compressa, Ray, Syn. Stirp. 30 Crumb of 



Bread Sponge, Ellis (Coral. 80, t. xvi. f. d.), Phil. Trans. 1705, t. x. 

 f. A — Cock's-comb Sponge, ib. t. xi. f. G — Spongia panacea and pa- 

 pillaris, Pallas, El. Zooph. 388, 391 — S. cristata and urens, Sol. Ellis. 

 Zooph. 180, 187. — S. compacta, Soiver. Brit. Misc. i. 45, t. xliii — S. 

 tomentosa and cristata, Mont. Wern. Mem. ii. 99. and 103. — S. papill. 



Grant, Edin. New Phil. Journ. ii. t. ii. f. 21 Encrusting rocks and the 



stalks of the larger fuci, very common. 



Crust about a quarter of an inch thick, yellow, uniform, with regular tu- 

 bular orifices where growing in a sheltered situation, but uneven where ex- 

 posed, the orifices short or elevated on crest-like ridges ; the canals are nu- 

 merous and wide ; when dry, the sponge is friable, not unlike the crumb of 

 bread ; when heated to destroy the animal matter, the remaining spicula, if 

 rubbed on the skin, excite a painful itching. The ova make their appear- 

 ance in spring. 



94. H. pcmicea. — Substance spreading, dense, surface even, 



the orifices large, rather imbedded ; spicula short, cylindrical, 



obtusely pointed at one extremity, rounded at the other. 



Spongia panicea", Grant, Edin. New Phil. Journ. i. 347 ; ii t. ii. f. 4.— 

 On rocks. 



