Microscopical Society. 393 



extending as a carbonized pellicle from one edge of the aperture to 

 the other. With reference to the point in dispute, there was sent 

 with the communication a portion of cuticle, which, after being im- 

 mersed in alcohol, distilled water and dilute hydrochloric acid, was, 

 when perfectly dry, examined by a high power and the membrane 

 distinctly seen ; it was more evident after the process of charring, 

 which process was so conducted as to obviate all error arising from 

 pressure. The tissue was placed on a slip of glass, and submitted to 

 the action of heat without being covered by another slip. Thus 

 both the supposed sources of error were avoided ; the one by the pre- 

 vious removal of organic mucus, and the other by a different mani- 

 pulation. 



The paper was accompanied with sketches of the stomata by Mr. 

 Lewis Aldous, the power employed being about 2000 linear ; and the 

 author concluded by stating, that Dr. Williams, after seeing the 

 membrane under this power, immediately approved of the process 

 which rendered it so distinctly visible. 



A paper was read descriptive of three species of Sponge, con- 

 taining some new forms of organization. By J. S. Bowerbank, Esq. 



The first specimen described is a Halichondria, which the author 

 has named Johnstoniana, in honour of Dr. Johnston of Berwick-on- 

 Tweed. 



The sponge is sessile, massive, and has a smooth encrusted sur- 

 face of a dark iron-gray colour ; the interior is of a dull yellow co- 

 lour and much resembles the crumb of bread. This sponge is re- 

 markable for the great variety in the forms of the siliceous spicula ; 

 of which the author describes three distinct kinds, each of which is 

 characteristic of a separate part of the animal : — 1st. Those of the 

 skeleton, which are mostly simple and slightly curved, having he- 

 mispherical terminations ; but occasionally they are triradiate or 

 multiradiate, and frequently branched. 2ndly. Those of the inter- 

 stitial fleshy matter of the sponge ; these are minute stellate bodies, 

 having their rays attenuating regularly to their apices, the number 

 of the rays varying from three to ten or twelve. Srdly. The spicula 

 of the crust or surface of the sponge ; they are very minute, some- 

 what fusiform, terminate abruptly, and have their surfaces regularly 

 tuberculated. 



The author also describes a fine vascular tissue which he observed 

 on the surfaces of the great excurrent canals. The gemmules are 

 oval bodies, having a siliceous crust which is filled with minute spi- 

 cula. This species was found attached to the Thatcher rock, near 

 Torquay, Devonshire. 



The second sponge described belongs to the new genus Duseideia, 

 proposed to be established by Dr. Johnston in his ' History of Bri- 

 tish Sponges.' 



This species was sent from Sidney, Australia, by Rupert Kirk, 

 Esq., after whom it is named Kirkii. It is sessile, massive, and some- 

 what compressed. The skeleton is coarsely fibrous and coralloid in 

 appearance, having numerous grains of sand separately imbedded in 

 its substance. The grains are not imbedded in the fibre from pres- 



