.'92 BRITISH SPONGIAD^. 



OYO-spinulate form its discrimination would have been 

 somewhat difl&cult. The basal terminations of all the 

 fully developed spicula are all purely ovoid, the smallest 

 end being the distal portion ; and this unusual form of 

 the basal mass prevails equally in the spicula of the 

 dermal membrane and in those of the skeleton tissues. 

 The shafts of the spicula are rather long, and rarely 

 exhibit even the slightest tendency to f usiformity. 



" There is no known British sponge with which this 

 species is likely to be confounded." 



46. Hymeniacidon subclavatus, Bow., ii, 209 ; iii, PI. 

 XXXVII, figs. 9—13. 



1870 Esperia sMScZauaf a, Schmidt. Spong. Atlant. Geb., p. 76. 



47. Hymeniacidon paupertas, Bow., ii, 223 ; iii, PI. 

 XXXVII, figs 4—8. 



1870 Desmacidon paupertas, Sclimidt. Spong. Atlant. Geb., 

 p. 76. 



48. Hymeniacidon Dujaedinii (Johnston), ii, 224; iii, 

 PI. XXXVIII, figs. 1—4. 



1867 Halisarca Dujardinii, Gray. Px-oc. Zool. Soc, p. 520. 



Habitat. — On Pecien opercularis and Anomia ejphip- 

 ■pium in the Minch, 1866 (N.). 



