Sponges from the Atlantic Ocean. 213 



come from an ordinary form of the anchorate. Arms, as they 

 approach each other, becoming compressed, widened, and 

 knife-shaped, with the thin edge inwards, and presenting, in 

 their fully developed state, fine parallel stria? close together on 

 the blade, which are perpendicular to its curved outer margin 

 (fig. 9, b) ; also presenting, before the union of the arms is 

 completed, a notch on the inner edge (fig. 9,«), which is filled 

 up at maturity, at which time the shaft becomes undistinguish- 

 able from the arms : average largest size of melon-shaped 

 form 12 by 7-6000ths of an inch in its greatest diameters 

 (fig. 9) ; that of the embryonic form 6-6000ths inch long 

 (fig. 12). Size of entire specimen about \\ inch in diameter 

 in all directions ; that of the tubercle about 1 to 2-6000ths 

 inch in diameter. 



Hah. Deep sea. 



Loc. Atlantic Ocean, between the north coast of Scotland 

 and the Faroe Islands. 



Obs. This specimen is alone ; and the label on the jar only 

 bears " Porcupine, 1869," which refers to the " voyage." It is 

 remarkable for the form of the full-grown anchorate, which 

 here also, but for the presence of all minor grades of develop- 

 ment leading up to the matured one, could hardly have been 

 understood. It is further remarkable for the general form and 

 structure of the body, although the presence of a stiff, bladder- 

 like envelope or dermis, similarly composed and filled with a 

 soft, parenchymatous, fibreless mass does not, as we shall see 

 hereafter in Histoderma appendiculatum, appear to be so much 

 confined to any particular species as to be a peculiarity of some 

 of the deep-sea sponges. It had grown on, and subsequently 

 partly round, the pebble at its base (PI. XIII. figs. 6 &7,bb) 7 

 which, in the otherwise unattached state of the sponge, must 

 at once have served to keep it more or less stationary, with 

 the same side always uppermost. Hence, probably, the re- 

 stricted position of the pore-area?. 



The alliance of the double form of skeleton-spicules here, as 

 well as their shape respectively, with those of Halichondria 

 incrustans, would seem to indicate that this sponge should be 

 placed under the heading " Halichondriai " in my 5th division 

 of sponges, viz. RaynerIjE. 



Esperia villosa, n. gen. et sp. PI. XIII. figs. 13-15, and 



PI. XV. fig. 36. 



General form massive, lobular, erect (fig. 13), growing from 

 a contracted portion of stout, naked fibre (fig. 13, a), whose main 

 filaments, being expanded at the ends, appear to have been torn 



