344 Mr. A. Haiicock on the Excavating Powers of Sponges, 



ment, the largest about 2i:th of an inch in diameter. Spicula 

 stout, nearly yyyth of an inch long, slightly and regularly 

 curved, gradually tapering to a sharp point at one end, and 

 with an oval swelling at the other, but not quite terminal, and 

 frequently ill-defined. 



This species inhabits red coral from the Mediterranean, and 

 completely destroys it ; the interior being reduced to a few large 

 irregularly angulated chambers divided by very thin walls, while 

 the surface remains comparatively uninjured, showing no signs 

 of the ravages within except a few circular punctures of no 

 great size, and at first so small as scarcely to attract attention. 

 The puncturing of the walls of the chambers is very strong 

 and regular in this species, and the spicula are characteristic, 

 and stouter than usual : the stems that unite the lobes are com- 

 paratively few. 



C. quadrata. PI. XV. fig. 6. 



Sponge composed of large, irregularly quadrate lobes, ^th of an 

 inch wide, with the angles obtuse, connected without apparent 

 order by several small, cylindrical stems passing irregularly from 

 all sides, occasionally in pairs ; sometimes enlarged and flattened 

 and arising from a depression in the side of the lobe : terminal 

 twigs rather short, fine and linear : papillae not very numerous, 

 about 2^^th of an inch in diameter, and placed rather far apart. 

 Spicula very large and stout, measuring 7\jth of an inch in length, 

 in form somewhat resembling a nine-pin; the shaft fusiform, 

 swelling in the centre to an extraordinary degree, and tapering 

 gradually to a fine point at one end ; the other terminates in an 

 exactly rounded head, very large, and distinguished from the 

 shaft by a dusky shadow caused by its rotundity. 



The animal of this species when dry is of a dark brown colour, 

 and may at once be recognized by the enormous development of 

 the spicula, which possess the utmost brillancy, and are very 

 striking objects in the microscope. The excavations are also 

 characteristic; their squareness of form, and numerous orifices for 

 the passage of the connecting stems arranged frequently in pairs 

 and flattened, sufiiciently distinguish this species. Only one or 

 two individuals have occurred, and those in Tridacna gigas. 



C. nodosa. PL XV. fig. 10. 



Sponge formed of a congeries of large, irregularly angulated 

 lobes disposed without apparent order, each measuring ^th of an 

 inch wide, and united to each other by several delicate, very 

 short, cylindrical stems : terminal twigs slender, a little produced, 

 cylindrical : papillae not numerous, considerably apart from each 

 other, the largest about ^^^^th of an inch in diameter. Spicula 



