40 PLATE XV. 



lated oscula are visible on its surface, and five of them 

 have the central orifice more or less open. Natural 

 size. 



Figs. 24, 25, 26. Three smaller specimens from 

 the same locality, for which I am indebted to my friend 

 Mr. Norman. These three specimens expanded by 

 immersion in water to a much greater proportional 

 extent than the larger ones represented by fig. 23. 

 They all exhibited the same mammillated oscula that 

 are so abundant on the largest specimen. Natural 

 size. 



Fig. 27. One of the sub-fusiformi, ovo-spinulate, 

 skeleton spicula. X 80 linear. 



Fig. 28. One of the minute acerate spicula from the 

 fasciculi of the dermal membrane. X 80 linear. 



Fig. 29. One of the short, stout, fusiformi-ovo- 

 spinulate, external, defensive spicula. X 80 linear. 



Fig. 30. One of the small, sub-fusiformi-ovo- 

 spinulate, tension spicula of the interstitial membranes. 

 X 80 linear. 



HALICNEMIA PATERA, Bowerbank. 



Vol. ii, p. 96, ' Mon. Brit. Spongiadse.' 



Fig. 31. Represents the upper or convex side of 

 the specimen I received from my late friend Mr. 

 Barlee in the dried state and of the natural size. 



Fig. 32. Exhibits the concave or under surface of 

 the same specimen in the dried state. Natural size. 



In vol. i, plate xxxii, fig. 363, a portion of a section 

 of this specimen is represented, exhibiting the mode of 

 the disposition of the spicula of the skeleton. X 25 

 linear. 



Fig. 364 in the same plate represents a portion of 

 the same section. X 108 linear. 



In the same volume, plate x, figs. 228 to 233 repre- 

 sent various forms of spinulate spicula from the same 

 specimen. 



