HALICHONDRIA. 97 



sponge is as usual formed by longitudinal and cross fibres con- 

 nected together and inosculating in every direction, so as to 

 form irregular meshes or pores : the fibre itself is smooth, pel- 

 lucid and tenacious, so that, when a piece is torn off and placed 

 under the microscope, no detached spicula appear, and they can 

 only be loosened from their glutinous matrix by heat or nitrous 

 acid. They are short, thickish, straight or slightly curved, and 

 pointed equally at both ends. 



" What is considered as an elegant slender variety of this 

 species is beautifully white, and has the branches more ascend- 

 ing and more tomentose. Perhaps it is the older specimens that 

 become palmated at the divarications, like the antlers of a buck. 

 Both these sponges may be likened to the horns of a deer in 

 their soft or velvety state, and one is probably the Spongia cer- 

 vicornis of Pallas." Montagu. 



Montagu gives the following description of his Sp. digita- 

 TA : " This very slender sponge is tough and flexible ; neither 

 the stem nor the branches are so large as a medium straw, slight- 

 ly compressed : the branches are distant, and usually terminate 

 in a cluster like the foot of a bird ; these slender terminal divi- 

 sions are from three to six in number. It is compact in its tex- 

 ture, and when examined under a microscope, appears granulat- 

 ed on the surface as if sprinkled with fine sand : the base of the 

 stem is usually ferruginous, the rest of a pale yellow-bi'own." 



Dr Fleming considers H. cervicornis to be a variety of H. 

 oculata, and I have seen specimens which favour this opinion, 

 but in general their distinction is easy enough. The spicula are 

 alike in both. 



The Spongia fruticosa of Esper, Spong. pi. 10, fig. 1, 2, 

 is allied to, or perhaps identical with this species ; but the Sp. 

 MURICATA, Lin. to which Esper's figure is referred by Lamarck, 

 is very different, and a native of the coast of Africa. I know 

 not by what oversight it has happened that the Sp. stuposa of 



