464 Zoological Society. 



Egyptian jaspers, Mocha stones, $c. — The author has examined 

 also numerous specimens of polished Egyptian jaspers, which, when 

 viewed as opake objects, by direct light and with a power of 150 

 linear, were found to consist of finely comminuted light buff or brown 

 irregular granules, cemented by semi-transparent silex, very much 

 resembling the state in which it exists in chalk-flints and greensand 

 cherts, and to the variations in its colouring matter the banded ap- 

 pearance of the jaspers is due. Imbedded, but very unequally in 

 the layers composing the jaspers, Mr. Bowerbank discovered hun- 

 dreds of beautiful foraminifera closely resembling those found in 

 chalk-flints, and often difficult to distinguish from the species found 

 in the Grignon sand of the calcaire grossier. 



The Mocha stones which the author has examined, presented no 

 indications of organic structure, the moss-like delineations and other 

 appearances, resembling beautiful, thin, reticulated tissues, being due 

 to dendritical or metallic infiltrations. 



In the larger pebbles of a mass of Herefordshire pudding-stone, 

 Mr, Bowerbank discovered the characteristic spongeous structure of 

 chalk-flints. 



In conclusion, the author dwells upon the difficulties attending 

 the study of the bodies which he has examined and described, in 

 consequence of the little attention which has been paid, with few 

 exceptions, to the structure of recent sponges ; and he states that 

 the aspect of the latter, when viewed by the unassisted eye, is so 

 different from that which it presents when seen under a high micro- 

 scopic power, that those who have not been accustomed to study 

 recent sponges with that aid would never recognise a similar struc- 

 ture in the fossils described by him. He also shows that the pre- 

 valence of keratose sponges over those belonging to the genus Hali- 

 chondria is what might naturally be expected, as the spicula which 

 form the skeleton of the latter would be less likely to be preserved 

 in their original position than the horny fibres of the former. 



Lastly, the author alludes to the great share which sponges have 

 had in the production of the solid strata of the earth's crust. 



ZOOLOGICAL SOCIETY. 



March 9, 1841. — James Whishaw, Esq., in the Chair. 

 A paper by Dr. Richardson, on some new or little known fishes 

 from the Australian seas, was read. The following is an abstract 

 of this paper. 



1 . Cheilodactylus gibbosus, forma 4 Cheilodactyli zonati, (h. e. 

 capite brevi, ore parvulo, dentibus brevibus setaceis ; dorso gibbo, 

 spind quartd longissimd f) radiis pinna dorsalis articulatis radios 

 spinosos numero plus duplo excedentibus . 

 Radii. P. 8'VI ; D. 17'36; V. 15; A. 3'8; C. 

 This species differs from the ordinary Cheilodactyli, and agrees 

 with the Japanese species discovered by the naturalists who accom- 

 panied Admiral Krusenstern, in the body being very high in the pec- 

 toral region, and tapering away in a lengthened manner posteriorly ; 



