BRITISH SPONGlADiE. 109 



required a microscopic power of about 300 linear to define 

 them well. . I could not detect the oscula in any of the 

 specimens I examined. 



Among the specimens of British sponges formerly be- 

 longing to Colonel Montagu, but now in the possession of 

 Professor Grant, there is a dwarf specimen of this species, 

 but it is not the type one figured by Montagu in vol. ii, 

 pi. 5, of the ' Weraerian Memoirs.* 



6. DiCTYOCYLiNDRUs ACULEATUs, Bowerhank. 



Halichondbiata aotjleata, Johnston. 



Sponge. Sessile, rising from numerous small slightly 

 expanded bases, branching and anastomosing. Sur- 

 face uneven, abundantly furnished with large spicula 

 projecting at nearly right angles to the axis. Oscula 

 and pores inconspicuous. Dermal membrane pellucid, 

 somewhat stout. Spicula. Of the skeleton ; acuate, 

 large, long and flexuous. Of the membranes; fusifor- 

 mi-acerate and occasionally fusiformi-acuate ; slender 

 and flexuous. Internal defensive spicula attenuato- 

 acuate, slightly but entirely spined, rare. Gemmules ? 

 Spherical or slightly oval, smooth, opaque, from once 

 to twice the largest diameter o£the skeleton spicula. 



Colour. — Purple-gray when dried. 



^a5«^a^.— Scarborough, Mr. Bean. 



Examined. — In the dried state. 



This interesting little species was found at Scarborough, 

 many years since, by my indefatigable friend, Mr. Bean. 

 He had labelled it Halichondria acuieata in his cabinet. I 

 have therefore adopted that appropriate specific name. 



-The height of the sponge does not exceed half an inch, 

 and its numerous primary branches are based on small 

 Balani; they are all nearly equal in height, and at their 

 distal extremities there are occasionally branches thrown 

 off" in a horizontal direction, which seems to indicate that 



