84 BRITISH SPONGES: 



slender, straight, and pointed at both ends, but, from their brit- 

 tleness, the points, especially of the protruding ones, are often 

 broken off abruptly. Those of the nucleus and parenchyma 

 are, in general, more than twic'e as stout as the cuticular ones, 

 and always simple and rigid ; but many of the latter are hair- 

 like, very slender, and three-pronged at their projecting extre- 

 mity, some with only two prongs, but these are probably de- 

 fective from injury. Professor Grant says that there are two 

 kinds of spicula, — a long straight fusiform sort, and the other 

 shorter, curved, of equal thickness throughout, and rather ob- 

 tusely pointed at both ends. The latter are about one-fourth 

 the length of the straight ones, and are found only in the rind, 

 where they abound. 



There is no appearance of polypes nor of any figured organ 

 in the structm'e of this sponge, nor is the interior traversed by 

 any canals, but there are a few irregular or scattered holes in 

 the parenchyma, which, however, have no passage at the sur- 

 face. Immersed in this parenchyma we likewise find a number 

 of oviform bodies, large enough to be visible to the naked eye, 

 and of an opake white colour. They are globose or ovate, slight- 

 ly uneven, and somewhat spiny, from the protruding ends of 

 spicula. WTien compressed between plates of glass they are 

 found to consist of a parenchyma traversed in every direction 

 by slender spicula, and apparently homogeneous in their com- 

 position. They are evidently the germs of future sponges, but 

 it is difficult to conceive by what means, or by what passages, 

 they escape from the parent, unless we suppose that by its death 

 and dissolution, it gives liberty and life to a numerous offspring. 

 — When fresh the sponge " exhales an offensive ammoniacal 



odour," which specimens preserved in spirits retain Mul- 



ler had seen a specimen which was five inches in diameter and 

 had a resemblance to the human skull. He tells us that when 

 living the species is of a fine yellow colour, but sometimes whit- 



