Sponges from the Atlantic Ocean. 401 



structure the same as in the foregoing species ; but the zone- 

 spicule and the stellate with which the internal sarcode is 

 charged are different. Thus the zone-spicule consists of a 

 long, smooth, round, straight shaft, pointed internally and 

 terminated externally by three simple, or unfurcated arms, 

 which are applied to the inner side of the petrous crust of 

 siliceous balls (fig. 46', a). Arms smooth, round, sharp- 

 pointed, expanded laterally and anteriorly, and slightly re- 

 curved ; shaft about 200- by 5-1800ths inch, arm about 47- 

 by 5-1800ths inch. Body-spicule about 210- by 3-1800ths 

 inch (fig. 46', c). Anchoring-spicules much the same as in 

 the last species (fig. 46', d). Sometimes, too, the arms of the 

 zone-spicule are furcated (fig. 46', h). Flesh-spicules of the 

 sarcode internally stelliform, of two sizes, viz.: — 1, the largest 

 (megastrellum), very large and plentiful, consisting of 3-7 arms 

 radiating irregularly from the centre, which has no body or 

 nucleus ; arm round, straight, sharp-pointed and microspined 

 throughout; total diameter of the megastrellum 6-1800ths inch, 

 arm 3-1800ths inch long (fig. 46', e, k) : 2, small body-stellate, 

 the same as the foregoing, but only 3-6000ths inch in diameter 

 (fig. 46', f I). The seven-armed form appears to be most 

 common in both the megastrellum and the body-stellate. Size 

 of specimen (fig. 46) 1 by 1^ inch long at the base and | inch 

 high ; longer than broad. 



Hah. Marine, on hard bodies. 



Loc. Probably from station 25 = 374 fathoms, near Cape 

 St. Vincent, where the fragments of Gorallistes BowerhanMi 

 in the jar bearing these numbers were dredged up ; for the 

 specimen is dry and has no label. 



Obs. There is only one specimen of this Geodia ; and, as 

 just stated, it is dry and has grown on the flat surface of a 

 large fragment of Corallistes BowerhanMi. 



Oeodia megastrella, var. Icevispina. 



(PI. XVI. fig. 47 &c.) 



Of this form there is only a fragment of the crust or cap- 

 ping about an inch square, to which a little of the internal 

 structure is still adherent. It was dredged in 292 fathoms, at 

 station 24, which would be a few miles north of Cape St. 

 Vincent, in the 1870 cruise, and agrees with the last species 

 in the form of the zone- and body-spicules and the presence of 

 the large stellate (megastrellum), but not in the surface stel- 

 late, the rays of which are simply truncated (fig. 47,f,k), and 

 the siliceous ball about ll-180(}ths inch in diameter (fig. 47, e). 

 The zone-spicule (fig. 47, a), too, is much smaller; for tlic shaft 



