194 Scientific Intelligence — Zoology. 



search for fossils and provided with all the necessary tools, including 

 magnifying glasses. Under the superintendence of their employer, 

 these men proceeded to open and work innumerable quarries, where 

 ever there seemed to be a promise of obtaining organic remains, and 

 solely for that object. They continued to labour uninterruptedly in 

 this manner for ten years, and the following statement will give some 

 idea of the rich harvest which they reaped. The Bohemian species 

 of all classes of fossils previously described by Sternberg, Boeck, and 

 Zenker, scarcely exceeded twenty in number, whereas M. Barrande, 

 during his investigation, procured 1100 species from the same area, 

 probably the most numerous assemblage of palaeozoic remains in the 

 world, and even more valuable, from the perfect state of their pre- 

 servation, than from their numbers. 



The 1100 species may be divided into the different classes nclarly 

 as follows : — 



Crustaceans, chiefly Tribolites, 250 species; Cephalopods, 250 

 species; Gasteropods and Pteropods, 160 species; Acephala, 130 

 species; Brachiopods, 200 species; Corals, &c. &c., 110 species; 

 Total 1100. — Quarterly Journal of the Geol. Soc, vol. vii., No. 

 26, p. xxii. 



ZOOLOGY. 



10. The boring power of Pholas Dactylus. — Having, while re- 

 siding here, opportunities of studying the Pholas Dactylus, I have 

 endeavoured during the last six months to discover how this mollusc 

 makes its hole, or crypt in the chalk ; by a chemical solvent ? by 

 absorption ? by ciliary currents ? or by rotatory motions ? 



My observations, dissections, and experiments, set at rest all con- 

 troversy in my own mind. Between twenty and thirty of these 

 creatures have been at work in lumps of chalk, in sea- water in a 

 finger glass and a pan, at my window, for the last three months. 



The Pholas Dactylus makes its hole by grating the chalk with its 

 rasp-like valves, licking it up when pulverized with its foot, forcing 

 it up through its principal or branchial siphon, and squirting it out 

 in oblong nodules. The crypt protects the Pholas from confervtB, 

 which, when they get at it, grow not merely outside, but even within 

 the lips of the valves, preventing the action of the siphons. 



In the foot there is a gelatinous spring or style, which even when 

 taken out, has great elasticity, and which seems the mainspring of 

 the motions of the Pholas Dactylus. — Communicated by Mr John 

 Robertson, Queen's Road, Brighton. 



11. Story of the Painting by Zeuxis. — The following anecdotes 

 prove, I think, that the ancient story of some fruit having been 

 painted by Zeuxis which birds were deceived by and pecked at, 

 may be quite true, and yet that the inference may bo wrong that 

 have been drawn from the fact, viz., that they were well painted, 



